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https://github.com/SCST-project/scst.git
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Web and docs updates
git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@3563 d57e44dd-8a1f-0410-8b47-8ef2f437770f
This commit is contained in:
Vladislav Bolkhovitin
356
qla2x00t/doc/qla2x00t-howto-debian.html
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qla2x00t/doc/qla2x00t-howto-debian.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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||||
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
|
||||
<title>How to build and configure QLogic target driver for 22xx/23xx/24xx/25xx adapters on Ubuntu/Debian</title>
|
||||
<style type="text/css">
|
||||
li {
|
||||
padding: 5px 0px 5px 0px;
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||||
}
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li div {
|
||||
margin-top: 2px;
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||||
margin-bottom: 10px;
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||||
}
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||||
div {
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||||
margin-top: 5px;
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||||
margin-bottom: 5px;
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||||
}
|
||||
.specialbox {
|
||||
margin-left: 10px;
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||||
width: 800px;
|
||||
border: 1px black dotted;
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||||
padding: 5px;
|
||||
background-color: lightgrey;
|
||||
}
|
||||
</style>
|
||||
</head>
|
||||
<body>
|
||||
<div style="width: 1024px;">
|
||||
|
||||
<div style="text-align: center; width: 1024px;"><strong>How to build and configure QLogic target driver for 22xx/23xx/24xx/25xx adapters on Ubuntu/Debian. A Step by step guide.</strong></div>
|
||||
|
||||
<br><br>
|
||||
|
||||
<div class="specialbox" style="width: 1024px;">
|
||||
<strong>Prerequisites:</strong>
|
||||
<ul style="list-style-type: decimal;">
|
||||
<li>Ubuntu/Debian 64bit base installation as minumum, fully updated.</li>
|
||||
<li>Working internet/network connection from this installation (for apt).</li>
|
||||
<li>Knowledge of configuring a Linux Kernel (a good base to work on is the configuration from the running kernel after installation)</li>
|
||||
<li>Check if there are any patches for your kernel <a href="https://scst.svn.sourceforge.net/svnroot/scst/trunk/scst/kernel/">here</a></li>
|
||||
</ul>
|
||||
</div>
|
||||
|
||||
<br>
|
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<div class="specialbox" style="width: 1024px;">
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||||
<b>Note 1:</b> I know this guide never builds a debian kernel package, i did not care about this, i only wanted to get the Generic SCSI Target Subsystem for Linux to work. I also know its not a good idea to compile anything as root, but again: i did not care about that either: the machine was a clean install, nobody will ever get hurt by me compiling a kernel or anything else as root.
|
||||
</div>
|
||||
<div class="specialbox" style="width: 1024px;">
|
||||
<b>Note 2:</b> I have to thank the original creator of <a>this guide</a>. I can not find your name but i can say i would not have been able to make it work wihtout it. I have based this document on that HowTo as a template.<br>
|
||||
</div>
|
||||
<br>
|
||||
<div style="text-align: center; width: 1024px;"> <strong>ON TARGET</strong></div>
|
||||
<ul style="list-style-type: decimal;">
|
||||
<li>Run the following apt command to install everything you might need or find useful:<br>
|
||||
|
||||
<div class="specialbox">
|
||||
# apt-get install linux-source subversion patch libcunit1-ncurses libncurses5-dev screen cramfsprogs bootcd-mkinitramfs lsscsi
|
||||
</div></li>
|
||||
|
||||
<li>Get the appropiate firmware for your QLogic card from<a href="ftp://ftp.qlogic.com/outgoing/linux/firmware">
|
||||
ftp://ftp.qlogic.com/outgoing/linux/firmware/</a> and put it under /lib/firmware.
|
||||
It is strongly recommended to use firmware version 5.x or higher for 24xx/25xx adapters. See
|
||||
<a href="http://sourceforge.net/mailarchive/forum.php?thread_name=4B4CD39F.6020401%40vlnb.net&forum_name=scst-devel">here</a>
|
||||
for more details why.
|
||||
|
||||
<br><br>
|
||||
|
||||
Without a firmware image during boot or when you manually insert the QLogic module, you might
|
||||
get the following error message in the logs (dmesg, /var/log/kern.log or /var/log/syslog)
|
||||
|
||||
<br><br>
|
||||
|
||||
< snip ><br>
|
||||
|
||||
qla2xxx 0000:13:00.0: Firmware image unavailable.<br>
|
||||
qla2xxx 0000:13:00.0: Failed to initialize adapter<br>
|
||||
< snip ><br><br>
|
||||
|
||||
In this case I have a Qlogic AR312A/HP FC1242SR with a good firmware preloaded.
|
||||
</li>
|
||||
|
||||
<li>Unzip it in /usr/src/<br>
|
||||
<div class="specialbox">
|
||||
# tar jxvf linux-2.x.xxx.tar.bz2
|
||||
</div></li>
|
||||
|
||||
<li>Create symlinks<br>
|
||||
<div class="specialbox">
|
||||
# pwd<br>
|
||||
/usr/src<br>
|
||||
# ln -s /usr/src/linux-2.x.xxx linux<br>
|
||||
# ln -s /usr/src/linux-2.x.xxx kernel
|
||||
</div></li>
|
||||
|
||||
<li>Get the SCST code. It is possibile either from the <a href="http://scst.sourceforge.net/downloads.html">SCST downloads page</a>
|
||||
or from the SVN code base.<br><br>
|
||||
|
||||
Below we will consider the case of the downloaded from the SVN code. For the release code everything is the same.
|
||||
You only need unpack all downloaded SCST archives in one directory. It then will contain similar content as
|
||||
~scst/trunk/ below.<br>
|
||||
<div class="specialbox">
|
||||
# svn co https://scst.svn.sourceforge.net/svnroot/scst
|
||||
</div>
|
||||
If the command returns successfully then you'll have 'scst'<br>
|
||||
directory under your current directory ( here it is /root )<br><br>
|
||||
</li>
|
||||
<li>Change directory to ~scst/trunk/<br>
|
||||
<div class="specialbox">
|
||||
# ls -1<br>
|
||||
AskingQuestions<br>
|
||||
doc<br>
|
||||
fcst<br>
|
||||
ibmvstgt<br>
|
||||
iscsi-scst<br>
|
||||
Makefile<br>
|
||||
mpt<br>
|
||||
mvsas_tgt<br>
|
||||
nightly<br>
|
||||
qla2x00t<br>
|
||||
qla_isp<br>
|
||||
qla_isp-release.patch<br>
|
||||
README<br>
|
||||
scripts<br>
|
||||
scst<br>
|
||||
scstadmin<br>
|
||||
scst_local<br>
|
||||
srpt<br>
|
||||
SVN_TAGS<br>
|
||||
usr<br>
|
||||
www
|
||||
</div>
|
||||
</li>
|
||||
<li>Patch the kernel (the kernel version you've downloaded in step 1)<br>
|
||||
<div class="specialbox">
|
||||
# cp /root/scst/trunk/scst/kernel/scst_exec_req_fifo-2.x.xxx.patch /usr/src/linux/<br>
|
||||
# cd /usr/src/linux/<br>
|
||||
# patch -p1 < scst_exec_req_fifo-2.x.xxx.patch<br>
|
||||
</div>
|
||||
</li>
|
||||
<li>Replace the QLogic FC driver code in the kernel source tree with the modified version
|
||||
of QLogic FC driver code from scst code base.<br>
|
||||
<div class="specialbox">
|
||||
# pwd<br>
|
||||
/root/scst/trunk<br>
|
||||
# mv /usr/src/linux/drivers/scsi/qla2xxx /usr/src/linux/drivers/scsi/qla2xxx_orig<br>
|
||||
# ln -s /root/scst/trunk/qla2x00t /usr/src/linux/drivers/scsi/qla2xxx
|
||||
</div>
|
||||
</li>
|
||||
<li>Now build the kernel.<br><br>
|
||||
Make sure you disable kernel hacking feature, and enable
|
||||
"Device Drivers->SCSI device support->SCSI low level drivers->Qlogic 2xxx target mode support"<br>
|
||||
(i.e. CONFIG_SCSI_QLA2XXX_TARGET=y)<br>
|
||||
Also turn OFF HIGHMEM4G|HIGHMEM64G, i.e.<br>
|
||||
<div class="specialbox">
|
||||
# grep -i highmem /usr/src/linux/.config<br>
|
||||
CONFIG_NOHIGHMEM=y<br>
|
||||
# CONFIG_HIGHMEM4G is not set<br>
|
||||
# CONFIG_HIGHMEM64G is not set
|
||||
</div>
|
||||
If you have system with more than 1GB of memory, consider to change CONFIG_VMSPLIT option to the corresponding value.<br>
|
||||
<div class="specialbox">
|
||||
# pwd<br>
|
||||
/usr/src/linux<br>
|
||||
# make menuconfig<br>
|
||||
# make bzImage<br>
|
||||
# make modules<br>
|
||||
# make modules_install<br>
|
||||
# make install
|
||||
</div>
|
||||
</li>
|
||||
<li>Reboot the machine and during boot select the modified kernel to boot from.</li>
|
||||
<li>Depending on your requirement (performance/debugging) apply the appropiate
|
||||
patches that comes with choose the appropriate SCST build mode. By default SCST has debug build mode.
|
||||
Here is how to switch to the release mode:<br>
|
||||
<div class="specialbox">
|
||||
# pwd<br>
|
||||
/root/scst/trunk<br>
|
||||
# make debug2release
|
||||
</div>
|
||||
</li>
|
||||
<li>First make sure that the link "/lib/modules/`uname -r`/build"<br>
|
||||
points to the current running kernel sources. Now build the modules.<br>
|
||||
|
||||
<ul style="list-style-type= lower-alpha;">
|
||||
<li> Build scst.<br>
|
||||
<div class="specialbox">
|
||||
# cd /root/scst/trunk/scst/src<br>
|
||||
# make all (here I am building everything)<br>
|
||||
# make install
|
||||
</div>
|
||||
</li>
|
||||
<li> Build QLogic target driver<br>
|
||||
<div class="specialbox">
|
||||
# cd /root/scst/trunk/qla2x00t/qla2x00-target/<br>
|
||||
# make<br>
|
||||
# make install
|
||||
</div>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
</li>
|
||||
<li>Insert the modules.<br>
|
||||
The driver modules will be installed in '/lib/modules/`you_kernel_version`/extra'.<br>
|
||||
In addition, scst.h, scst_debug.h as well as Module.symvers or
|
||||
Modules.symvers will be copied to '/usr/local/include/scst'.<br> The first
|
||||
file contains all SCST's public data definition, which are used by
|
||||
target drivers. The other ones support debug messages logging and build process.<br>
|
||||
<div class="specialbox">
|
||||
# ls -l /lib/modules/`uname -r`/extra<br>
|
||||
total 232<br>
|
||||
drwxr-xr-x 2 root root 4096 Jun 20 18:43 dev_handlers<br>
|
||||
-rw-r--r-- 1 root root 36756 Jun 20 18:46 qla2x00tgt.ko<br>
|
||||
-rw-r--r-- 1 root root 160192 Jun 20 18:46 qla2xxx.ko <br>
|
||||
-rw-r--r-- 1 root root 190848 Jun 20 18:43 scst.ko<br><br>
|
||||
# ls -l /lib/modules/`uname -r`/extra/dev_handlers<br>
|
||||
total 192<br>
|
||||
-rw-r--r-- 1 root root 11757 Jun 20 18:43 scst_cdrom.ko<br>
|
||||
-rw-r--r-- 1 root root 10111 Jun 20 18:43 scst_changer.ko<br>
|
||||
-rw-r--r-- 1 root root 12420 Jun 20 18:43 scst_disk.ko<br>
|
||||
-rw-r--r-- 1 root root 12449 Jun 20 18:43 scst_modisk.ko<br>
|
||||
-rw-r--r-- 1 root root 10131 Jun 20 18:43 scst_processor.ko<br>
|
||||
-rw-r--r-- 1 root root 10081 Jun 20 18:43 scst_raid.ko<br>
|
||||
-rw-r--r-- 1 root root 12563 Jun 20 18:43 scst_tape.ko<br>
|
||||
-rw-r--r-- 1 root root 37937 Jun 20 18:43 scst_user.ko<br>
|
||||
-rw-r--r-- 1 root root 50194 Jun 20 18:43 scst_vdisk.ko
|
||||
</div>
|
||||
Where:<br>
|
||||
- scst - SCST itself<br>
|
||||
- scst_disk - device handler for disks (type 0)<br>
|
||||
- scst_tape - device handler for tapes (type 1)<br>
|
||||
- scst_processor - device handler for processors (type 3)<br>
|
||||
- scst_cdrom - device handler for CDROMs (type 5)<br>
|
||||
- scst_modisk - device handler for MO disks (type 7)<br>
|
||||
- scst_changer - device handler for medium changers (type 8)<br>
|
||||
- scst_raid - device handler for storage array controller (e.g. raid) (type C)<br>
|
||||
- scst_vdisk - device handler for virtual disks (file, device or ISO CD image).<br>
|
||||
- scst_user - user space device handler<br><br>
|
||||
|
||||
You can insert any of these modules by 'modprobe' program, I've inserted all
|
||||
the modules !!!<br>
|
||||
<div class="specialbox">
|
||||
# for _mod in scst qla2xxx qla2x00tgt scst_vdisk scst_user scst_disk [...etc snip]; do modprobe $_mod; done
|
||||
</div><br>
|
||||
|
||||
< snip from dmesg ><br><br>
|
||||
|
||||
scst: SCST version 2.0.0 loaded successfully (max mem for commands 16251MB, per device 6500MB)<br>
|
||||
scst: Enabled features: TRACING<br>
|
||||
scst: Target template qla2x00tgt registered successfully<br>
|
||||
scst: Virtual device handler vdisk for type 0 registered successfully<br>
|
||||
scst: Virtual device handler "scst_user" registered successfully<br><br>
|
||||
|
||||
< snip from dmesg >
|
||||
</li>
|
||||
<li>Now let's create our virtual device:<br>
|
||||
<div class="specialbox">
|
||||
# dd if=/dev/zero of=/mnt/disk1 bs=1024k count=512<br>
|
||||
512+0 records in<br>
|
||||
512+0 records out<br>
|
||||
# ls -l /mnt/disk1<br>
|
||||
-rw-r--r-- 1 root root 536870912 Jun 23 13:27 /mnt/disk1<br>
|
||||
# file /mnt/disk1<br>
|
||||
/mnt/disk1: data
|
||||
</div>
|
||||
</li>
|
||||
<li>To see the device remotely, we have to add it to at least in the LUNs set for our target.<br>
|
||||
We must have LUN 0 (LUs numeration must not start from, e.g., 1).<br><br>
|
||||
|
||||
The simplest way to do that is to write an scstadmin's config file:<br><br>
|
||||
<div class="specialbox">
|
||||
HANDLER vdisk_fileio {<br>
|
||||
DEVICE disk1 {<br>
|
||||
filename /mnt/disk1<br>
|
||||
}<br>
|
||||
}<br><br>
|
||||
|
||||
TARGET_DRIVER qla2x00t {<br>
|
||||
TARGET 25:00:00:f0:98:87:92:f3 {<br>
|
||||
LUN 0 disk1<br><br>
|
||||
|
||||
enabled 1<br>
|
||||
}<br>
|
||||
}
|
||||
</div><br>
|
||||
|
||||
To use it, we need to install scstadmin:<br><br>
|
||||
|
||||
<div class="specialbox">
|
||||
# pwd<br>
|
||||
/root/scst/trunk/scstadmin<br>
|
||||
# make<br>
|
||||
# make install
|
||||
</div><br>
|
||||
|
||||
Let's save our config file as /etc/scst.conf<br><br>
|
||||
|
||||
Now run scstadmin:<br><br>
|
||||
|
||||
<div class="specialbox">
|
||||
# scstadmin -config /etc/scst.conf
|
||||
|
||||
Collecting current configuration: done.<br><br>
|
||||
|
||||
-> Checking configuration file 'qq' for errors.<br>
|
||||
-> Done, 0 warnings found.<br><br>
|
||||
|
||||
-> Opening device 'disk1' using handler 'vdisk_fileio': done.<br>
|
||||
-> Adding device 'disk1' at LUN 0 to driver/target 'qla2x00t/25:00:00:f0:98:87:92:f3': done.<br>
|
||||
-> Enabling driver/target 'qla2x00t/25:00:00:f0:98:87:92:f3': done.<br><br>
|
||||
|
||||
All done.
|
||||
</div><br>
|
||||
|
||||
The same can be done directly via SCST's sysfs interface:<br><br>
|
||||
|
||||
<div class="specialbox">
|
||||
# echo "add_device disk1 filename=/mnt/disk1" >/sys/kernel/scst_tgt/handlers/vdisk_fileio/mgmt<br>
|
||||
# echo "add disk1 0" >/sys/kernel/scst_tgt/targets/qla2x00t/25:00:00:f0:98:87:92:f3/luns/mgmt<br>
|
||||
# echo "1" >/sys/kernel/scst_tgt/targets/qla2x00t/25:00:00:f0:98:87:92:f3/enabled
|
||||
</div>
|
||||
</li>
|
||||
</ul>
|
||||
|
||||
<div style="text-align: center; width: 1024px;"><strong>ON INITIATOR</strong></div>
|
||||
|
||||
<ul style="list-style-type: decimal;">
|
||||
<li>< snip from README ><br>
|
||||
Without loading appropriate device handler, corresponding device
|
||||
will be invisible for remote initiators, hence we have to
|
||||
add them manully.<br>
|
||||
< snip from README ><br><br>
|
||||
|
||||
But as I've already loaded the device handler(scst_vdisk) on the target,
|
||||
hence I don't need to perform step 17. <br><br>
|
||||
|
||||
</li>
|
||||
<li>After enabling the target mode on the target (see step 16),
|
||||
to see new targets and devices you need either to rescan
|
||||
initiator(s) manually, for example, by rmmod/modprobe the
|
||||
corresponding FC device module on the initiator, or reboot the initiator itself.
|
||||
Automatic discovery isn't supported by all known initiators,
|
||||
so you need a way to make SCSI subsystem on the initiator to do the new devices discovery and hence be able to see
|
||||
the new devices attached.<br><br>
|
||||
|
||||
Alternatively, if your initiator already connected to the target and you simply added new devices to it, you can try to run
|
||||
a manual rescan by:<br>
|
||||
<div class="specialbox">
|
||||
# echo "- - -" >/sys/class/scsi_host/hostX/scan
|
||||
</div>
|
||||
Where X is the host number
|
||||
</li>
|
||||
</ul>
|
||||
<div style="text-align: center; width: 1024px;"><strong>ALL DONE, YOU SHOULD NOW HAVE A WORKING TARGET!</strong></div>
|
||||
</div>
|
||||
</body>
|
||||
</html>
|
||||
@@ -37,6 +37,7 @@
|
||||
<h1>Comparison</h1>
|
||||
<ul class="sidemenu">
|
||||
<li><a href="comparison.html">Features comparison</a></li>
|
||||
<li><a href="scstvslio.html">SCST vs LIO/TCM</a></li>
|
||||
<li><a href="scstvsstgt.html">SCST vs STGT</a></li>
|
||||
<li><a href="mc_s.html">MC/S vs MPIO</a></li>
|
||||
</ul>
|
||||
@@ -51,7 +52,7 @@
|
||||
mailing list and it will be corrected.
|
||||
</p>
|
||||
|
||||
<p><small>As on September 2010. Partially updated in December 2010.</small></p>
|
||||
<p><small>As on June 2011.</small></p>
|
||||
|
||||
<table bgcolor="#F0F0F0" border="1" cellspacing="1" cellpadding="7" style="text-align:center" width="620">
|
||||
|
||||
@@ -60,7 +61,7 @@
|
||||
</td><td><b><a href="http://scst.sourceforge.net/" title="http://scst.sourceforge.net/" rel="nofollow">SCST</a></b>
|
||||
</td><td><b><a href="http://stgt.berlios.de/" title="http://stgt.berlios.de/" rel="nofollow">STGT</a></b>
|
||||
</td><td><b><a href="http://iscsitarget.sourceforge.net/" title="http://iscsitarget.sourceforge.net/" rel="nofollow">IET</a></b>
|
||||
</td><td><b><a href="http://linux-iscsi.org/" title="http://linux-iscsi.org/" rel="nofollow">LIO</a></b>
|
||||
</td><td><b><a href="scstvslio.html">LIO/TCM</a></b>
|
||||
</td></tr>
|
||||
|
||||
<tr bgcolor="#E0E0E0">
|
||||
@@ -69,7 +70,7 @@
|
||||
<tr>
|
||||
<td align="left"><b>Upstream kernel</b></td> <td> - </td> <td>Interface with
|
||||
in-kernel target
|
||||
drivers</td> <td> - </td> <td> - </td>
|
||||
drivers (obsolete)</td> <td> - </td> <td> <a href="scstvslio.html">Since 2.6.38</a></td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Generic Target Engine</b></td> <td> + </td> <td> + </td> <td> iSCSI only </td> <td> + </td>
|
||||
@@ -80,22 +81,19 @@
|
||||
</sup> </td> <td> - </td> <td> Kernel only </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Stability</b></td> <td> + </td> <td> +
|
||||
<sup><A HREF="#3">3</A>
|
||||
</sup> </td> <td> + </td> <td> Probably (no released packages) </td>
|
||||
<td align="left"><b>Stability</b></td> <td> + </td> <td> + </td> <td> + </td> <td> Probably (no released packages) </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Performance <sup><A HREF="#4">4</A></sup></b></td> <td> ***** <sup>
|
||||
<A HREF="#5">5</A>
|
||||
</sup></td> <td> ***</td> <td> **** </td> <td> ****
|
||||
<sup><A HREF="#6">6</A></sup></td>
|
||||
<td align="left"><b>Performance <sup><A HREF="#3">3</A></sup></b></td> <td> ***** <sup>
|
||||
<A HREF="#4">4</A>
|
||||
</sup></td> <td> ***</td> <td> **** </td> <td> **** </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<th align="left"> Zero-copy passing data between target and
|
||||
backend drivers</th> <td> + <sup>
|
||||
<A HREF="#7">7</A>
|
||||
<A HREF="#5">5</A>
|
||||
</sup></td> <td> + <sup>
|
||||
<A HREF="#8">8</A>
|
||||
<A HREF="#6">6</A>
|
||||
</sup> </td> <td> + </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
@@ -129,7 +127,7 @@ transfer values (Wide (parallel) SCSI, SAS)</b></td> <td> + </td> <td> - </td
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Advanced devices access control
|
||||
<sup><A HREF="#10">10</A></sup></b></td> <td> + </td> <td> - </td> <td> - </td> <td> + </td>
|
||||
<sup><A HREF="#8">8</A></sup></b></td> <td> + </td> <td> - </td> <td> - </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Automatic sessions reassignment (changes in the
|
||||
@@ -145,10 +143,10 @@ resized through AENs or Unit Attentions (initiators can instantly see
|
||||
any target reconfiguration in a PnP-like manner)</b></td> <td> + </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Bidirectional Commands</b></td> <td> +</td> <td> + </td> <td> - </td> <td> - </td>
|
||||
<td align="left"><b>Bidirectional Commands</b></td> <td> +</td> <td> + </td> <td> - </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Extended CDB (size >16 bytes)</b></td> <td> +</td> <td> + </td> <td> - </td> <td> - </td>
|
||||
<td align="left"><b>Extended CDB (size >16 bytes)</b></td> <td> +</td> <td> + </td> <td> - </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Descriptor sense support</b></td> <td> + </td> <td> + </td> <td> - </td> <td> - </td>
|
||||
@@ -159,12 +157,12 @@ any target reconfiguration in a PnP-like manner)</b></td> <td> + </td> <td> -
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Safe RESERVE/RELEASE implementation according to
|
||||
SCSI requirements <sup><A HREF="#12">12</A></sup></b></td> <td> Safe </td> <td> Safe </td> <td> Safe from
|
||||
SCSI requirements <sup><A HREF="#10">10</A></sup></b></td> <td> Safe </td> <td> Safe </td> <td> Safe from
|
||||
v1.4.18</td> <td> Not safe </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Safe implementation of Task Management commands
|
||||
<sup><A HREF="#13">13</A></sup></b></td> <td> Safe </td> <td> Not safe </td> <td> Not safe </td> <td> LUN RESET - safe.
|
||||
<sup><A HREF="#11">11</A></sup></b></td> <td> Safe </td> <td> Not safe </td> <td> Not safe </td> <td> LUN RESET - safe.
|
||||
Other TM commands not
|
||||
implemented. </td>
|
||||
</tr>
|
||||
@@ -172,11 +170,11 @@ SCSI requirements <sup><A HREF="#12">12</A></sup></b></td> <td> Safe </td> <td
|
||||
<td align="left"><b>Support for SCSI task attributes, including
|
||||
ORDERED commands</b></td> <td> + </td> <td> + </td> <td> -, <br> data
|
||||
corruption possible
|
||||
<sup><A HREF="#14">
|
||||
14</A></sup></td> <td> -, <br>data
|
||||
<sup><A HREF="#12">
|
||||
12</A></sup></td> <td> -, <br>data
|
||||
corruption possible
|
||||
<sup><A HREF="#14">
|
||||
14</A></sup> </td>
|
||||
<sup><A HREF="#12">
|
||||
12</A></sup> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Persistent (SCSI-3) Reservations
|
||||
@@ -188,8 +186,11 @@ ORDERED commands</b></td> <td> + </td> <td> + </td> <td> -, <br> data
|
||||
Through Power Loss Persistent Reservation data</b></td> <td> Durable </td> <td>Not supported</td> <td> - </td> <td> Not durable </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>ALUA</b></td> <td> - </td> <td> - </td> <td> - </td> <td> +/-<sup><A HREF="#22">
|
||||
22</A></sup></td>
|
||||
<td align="left"><b>ALUA</b></td> <td> +/- (Implicit
|
||||
only)<sup>
|
||||
<A HREF="#20">20</A>
|
||||
</sup> </td> <td> - </td> <td> - </td> <td> +/-<sup><A HREF="#20">
|
||||
20</A></sup></td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Failover Clustering</b></td> <td> + </td> <td> + </td> <td> + </td> <td> + </td>
|
||||
@@ -228,11 +229,11 @@ to allocate too much memory for buffers and go into OOM state
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Configuration tool with ability to automatically
|
||||
apply changes in the config file on fly without any restarts</b></td> <td> scstadmin </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
apply changes in the config file on fly without any restarts</b></td> <td> scstadmin </td> <td> - </td> <td> - </td> <td> rtsadmin? </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>SCSI MIBs</b></td> <td> - </td> <td> - </td> <td> - </td> <td> +-
|
||||
<sup><A HREF="#15">15</A></sup></td>
|
||||
<sup><A HREF="#13">13</A></sup></td>
|
||||
</tr>
|
||||
|
||||
|
||||
@@ -243,19 +244,16 @@ apply changes in the config file on fly without any restarts</b></td> <td> scsta
|
||||
<td align="left"><b>iSCSI</b></td> <td> + </td> <td> + </td> <td> + </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>QLogic (Fibre Channel)</b></td> <td> + </td> <td> - </td> <td> - </td> <td> Preliminary
|
||||
(just added) </td>
|
||||
<td align="left"><b>QLogic (Fibre Channel)</b></td> <td> + </td> <td> - </td> <td> - </td> <td> Preliminary</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Emulex (Fibre Channel and FCoE)</b></td> <td> + </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>SRP</b></td> <td> + </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
<td align="left"><b>SRP</b></td> <td> + </td> <td> - </td> <td> - </td> <td> Preliminary </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>iSER</b></td> <td> - </td> <td> +
|
||||
<sup><A HREF="#3">3</A>
|
||||
</sup> </td> <td> - </td> <td> - </td>
|
||||
<td align="left"><b>iSER</b></td> <td> - </td> <td> + </td> <td> - </td> <td> - </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Marvell (SAS)</b></td> <td> Beta </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
@@ -273,11 +271,11 @@ apply changes in the config file on fly without any restarts</b></td> <td> scsta
|
||||
(not completed) </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>IBM pSeries Virtual SCSI</b></td> <td> + </td> <td> + </td> <td> - </td> <td> - </td>
|
||||
<td align="left"><b>IBM pSeries Virtual SCSI</b></td> <td> + </td> <td> + </td> <td> - </td> <td> Preliminary </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Local access to emulated backstorage devices
|
||||
<sup><A HREF="#9">9</A></sup></b></td> <td> scst_local </td> <td> - </td> <td> - </td> <td> tcm_loop </td>
|
||||
<sup><A HREF="#7">7</A></sup></b></td> <td> scst_local </td> <td> - </td> <td> - </td> <td> tcm_loop </td>
|
||||
</tr>
|
||||
<tr bgcolor="#E0E0E0">
|
||||
<td colspan="5"> <b>Supported backstorage</b>
|
||||
@@ -302,35 +300,33 @@ apply changes in the config file on fly without any restarts</b></td> <td> scsta
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>SCSI pass-through
|
||||
<sup><A HREF="#16">16</A></sup></b></td> <td> + </td> <td> Single
|
||||
<sup><A HREF="#14">14</A></sup></b></td> <td> + </td> <td> Single
|
||||
initiator only, not
|
||||
enforced, limited
|
||||
functionality for tapes
|
||||
<sup>
|
||||
<A HREF="#17">17</A>
|
||||
enforced<sup>
|
||||
<A HREF="#15">15</A>
|
||||
</sup> </td> <td> - </td> <td> Single initiator only, not enforced,
|
||||
limited functionality for tapes
|
||||
<sup><A HREF="#17">17</A></sup></td>
|
||||
<sup><A HREF="#15">15</A></sup></td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Zero-copy data read/write to/from backstorage
|
||||
</b></td> <td>BLOCKIO, user space
|
||||
FILEIO in O_DIRECT mode,
|
||||
pass-through <sup>
|
||||
<A HREF="#18">18</A>
|
||||
<A HREF="#16">16</A>
|
||||
</sup></td> <td> - <sup>
|
||||
<A HREF="#8">8</A>
|
||||
<A HREF="#6">6</A>
|
||||
</sup> </td> <td> BLOCKIO </td> <td> BLOCKIO, pass-
|
||||
through </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Cache safe<sup><A HREF="#11">11</A></sup>
|
||||
<td align="left"><b>Cache safe<sup><A HREF="#9">9</A></sup>
|
||||
FILEIO</b></td> <td> Safe </td> <td>Safe only RDWR
|
||||
backend</td> <td> Safe </td> <td> + (just added) </td>
|
||||
backend</td> <td> Safe </td> <td> Safe </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Cache safe<sup><A HREF="#11">11</A></sup>
|
||||
BLOCKIO</b></td> <td> Safe </td> <td> - </td> <td> Not safe </td> <td> + (just added)</td>
|
||||
<td align="left"><b>Cache safe<sup><A HREF="#9">9</A></sup>
|
||||
BLOCKIO</b></td> <td> Safe </td> <td> - </td> <td> Not safe </td> <td> Safe </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>4k sectors support in pass-through mode</b></td> <td> + </td> <td> - </td> <td> - </td> <td> ? </td>
|
||||
@@ -352,7 +348,7 @@ CD devices</b></td> <td> - </td> <td> + </td> <td> - </td> <td> - </td>
|
||||
devices (VTL)</b></td> <td> - </td> <td>Experimental</td> <td> - </td> <td> - </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Thin provisioning support</b></td> <td>+<br></td> <td> - </td> <td> - </td> <td> + (just added) </td>
|
||||
<td align="left"><b>Thin provisioning support</b></td> <td>+<br></td> <td> - </td> <td> - </td> <td> + </td>
|
||||
</tr>
|
||||
|
||||
<tr bgcolor="#E0E0E0">
|
||||
@@ -374,10 +370,10 @@ devices (VTL)</b></td> <td> - </td> <td>Experimental</td> <td> - </td> <
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Zero-copy data send/receive</b></td> <td> Send only<sup>
|
||||
<A HREF="#19">19</A>
|
||||
<A HREF="#17">17</A>
|
||||
</sup> </td> <td> In some cases,
|
||||
send only <sup>
|
||||
<A HREF="#8">8</A>
|
||||
<A HREF="#6">6</A>
|
||||
</sup> </td> <td> Send only</td> <td> Send only </td>
|
||||
</tr>
|
||||
<tr>
|
||||
@@ -418,38 +414,38 @@ target reconfiguration in a PnP-like manner)</b></td> <td> + </td> <td> - </t
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Safe implementation of Task Management commands
|
||||
<sup><A HREF="#13">13</A></sup></b></td> <td> Safe </td> <td> Not safe </td> <td> Not safe </td> <td> ABORT TASK - not safe,
|
||||
<sup><A HREF="#11">11</A></sup></b></td> <td> Safe </td> <td> Not safe </td> <td> Not safe </td> <td> ABORT TASK - not safe,
|
||||
LUN RESET - safe,
|
||||
other TM commands not
|
||||
implemented. </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Safe implementation of connections and sessions
|
||||
reinstatement <sup><A HREF="#20">20</A></sup></b></td> <td> Safe </td> <td> Not safe </td> <td> Not safe </td> <td> Not safe </td>
|
||||
reinstatement <sup><A HREF="#18">18</A></sup></b></td> <td> Safe </td> <td> Not safe </td> <td> Not safe </td> <td> Not safe </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Usage of hardware instructions for digest
|
||||
calculations, if available</b></td> <td> + </td> <td> - </td> <td> - </td> <td> + (just added) </td>
|
||||
calculations, if available</b></td> <td> + </td> <td> - </td> <td> - </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Each connection multithreaded digest calculation
|
||||
</b></td> <td> + </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Safe restart <sup><A HREF="#21">21</A></sup>
|
||||
<td align="left"><b>Safe restart <sup><A HREF="#19">19</A></sup>
|
||||
</b></td> <td> Safe </td> <td> ? </td> <td> Not safe before
|
||||
v1.4.18. After -
|
||||
probably safe.</td> <td> ?</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>iSCSI MIBs</b></td> <td> - </td> <td> - </td> <td> - </td> <td> +-
|
||||
<sup><A HREF="#15">15</A></sup></td>
|
||||
<sup><A HREF="#13">13</A></sup></td>
|
||||
</tr>
|
||||
<tr bgcolor="#E0E0E0">
|
||||
<td colspan="5"> <b>Local access target</b>
|
||||
</td></tr>
|
||||
<tr>
|
||||
<td align="left"><b>Bidirectional support</b></td> <td> + </td> <td> - </td> <td> - </td> <td> - </td>
|
||||
<td align="left"><b>Bidirectional support</b></td> <td> + </td> <td> - </td> <td> - </td> <td> + </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td align="left"><b>Support for AENs (initiators can instantly see any
|
||||
@@ -466,54 +462,43 @@ target reconfiguration in a PnP-like manner)</b></td> <td> + </td> <td> - </t
|
||||
|
||||
<p><A NAME="2"></A> 2. All iSCSI management implemented in user space and actual data transfers in kernel space without user space involved.</p>
|
||||
|
||||
<p><A NAME="3"></A> 3. ISER target driver has long known (since Feb 2008) data corruption problem, which localization hasn't been
|
||||
determined yet and might be in the STGT core. See
|
||||
<a href="http://lists.berlios.de/pipermail/stgt-devel/2008-February/001367.html">here</a>,
|
||||
<a href="http://lists.wpkg.org/pipermail/stgt/2009-February/002630.html">here</a> and
|
||||
<a href="http://lists.wpkg.org/pipermail/stgt/2010-August/004076.html">here</a>.</p>
|
||||
|
||||
<p><A NAME="4"></A> 4. The result "in average" is listed. One target can be better somewhere, another one somewhere else. Although manual tuning of target and
|
||||
<p><A NAME="3"></A> 3. The result "in average" is listed. One target can be better somewhere, another one somewhere else. Although manual tuning of target and
|
||||
system parameters tends the restore the difference listed in the comparison. You can find example measurements <a href="vl_res.txt">here</a>,
|
||||
<a href="bart_res.txt">here</a> and <a href="tomasz_res.txt">here</a>.</p>
|
||||
|
||||
<p><A NAME="5"></A> 5. All SCST and its drivers' kernel patches supposed to be applied and SCST with the drivers built in the release or performance build.
|
||||
<p><A NAME="4"></A> 4. All SCST and its drivers' kernel patches supposed to be applied and SCST with the drivers built in the release or performance build.
|
||||
Without the kernel patches SCST performance will be at "****+" level, except for the case, when user space backstorage handler used
|
||||
with iSCSI-SCST iSCSI target driver, where performance will be at "***+" level.</p>
|
||||
|
||||
<p><A NAME="6"></A> 6. There is no performance data for LIO, which allow to make a direct comparison with other targets.
|
||||
The conclusion was made based on source code study. LIO should have performance on the IET level or less,
|
||||
because of more processing overhead. It might be much less for small block sizes. Also the single I/O thread per-device
|
||||
approach LIO has is not optimal in many cases.</p>
|
||||
|
||||
<p><A NAME="7"></A> 7. In SCST data are always passed in zero-copy manner between target and backend drivers without need for any
|
||||
<p><A NAME="5"></A> 5. In SCST data are always passed in zero-copy manner between target and backend drivers without need for any
|
||||
additional kernel patches, except in case, when local access (scst_local) used with user space backend. </p>
|
||||
|
||||
<p><A NAME="8"></A> 8. Some zero-copy functionality isn't available from user space, sometimes fundamentally.
|
||||
<p><A NAME="6"></A> 6. Some zero-copy functionality isn't available from user space, sometimes fundamentally.
|
||||
For instance, zero-copy FILEIO with page cache or zero-copy send to a socket. Also STGT can't use splice() for in-kernel
|
||||
target drivers, because it has memory management in user space. To use splice() with socket-based user space target drivers
|
||||
STGT would need a deep redesign of internal interactions between target drivers, core and backend handlers. But in
|
||||
some cases STGT can use zero-copy sendfile().</p>
|
||||
|
||||
<p><A NAME="9"></A> 9. Local access to emulated backstorage devices" means that you can access emulated by a SCSI target devices
|
||||
<p><A NAME="7"></A> 7. "Local access to emulated backstorage devices" means that you can access emulated by a SCSI target devices
|
||||
locally on the target host. For instance, you can mount your ISO image from emulated by the target
|
||||
CDROM device locally on the target host.</p>
|
||||
|
||||
<p><A NAME="10"></A> 10. "Advanced devices access control" means that different initiators can see different sets
|
||||
<p><A NAME="8"></A> 8. "Advanced devices access control" means that different initiators can see different sets
|
||||
of devices from the same target. This feature is required for hardware targets, which don't have ability
|
||||
to create virtual targets.</p>
|
||||
|
||||
<p><A NAME="11"></A> 11. "Cache safe" means that cache synchronization commands (SYNCHRONIZE_CACHE and FUA attribute) from initiators perform
|
||||
<p><A NAME="9"></A> 9. "Cache safe" means that cache synchronization commands (SYNCHRONIZE_CACHE and FUA attribute) from initiators perform
|
||||
what they expected to perform, i.e. push all the requested blocks from all caches, including devices' caches,
|
||||
to non-volatile media.</p>
|
||||
|
||||
<p><A NAME="12"></A> 12. SCSI requires that if an initiator clears reservation held by another initiator, the reservation holder must be notified
|
||||
<p><A NAME="10"></A> 10. SCSI requires that if an initiator clears reservation held by another initiator, the reservation holder must be notified
|
||||
about the reservation clearance. Otherwise, several initiators can at the same time change supposed to be protected by the
|
||||
reservation data, which can corrupt them. This is what was called
|
||||
<a href="http://communities.vmware.com/thread/53797?tstart=0&start=15">"Russian roulette with your data"</a> on the VMware
|
||||
community forum by someone working for VMware. But, sure, it can affect not only VMware, but also any other cluster
|
||||
implementation, relying on this functionality.</p>
|
||||
|
||||
<p><A NAME="13"></A> 13. After a task management command completed and before the corresponding response was sent to the initiator, who sent that task management
|
||||
<p><A NAME="11"></A> 11. After a task management command completed and before the corresponding response was sent to the initiator, who sent that task management
|
||||
command, all the affected SCSI commands must get into a state, where they can't affect following after
|
||||
the tasks management response commands from this initiator. This is the safe implementation.
|
||||
The unsafe implementation only marks all the affected
|
||||
@@ -523,44 +508,43 @@ target reconfiguration in a PnP-like manner)</b></td> <td> + </td> <td> - </t
|
||||
SCSI command, which initiator will send after it received the task management response thinking
|
||||
that all the aborted commands actually fully aborted. This could lead to a data corruption.</p>
|
||||
|
||||
<p><A NAME="14"></A> 14. Both IET and LIO report in INQUIRY command response support for full task management model. But they process ORDERED
|
||||
<p><A NAME="12"></A> 12. Both IET and LIO report in INQUIRY command response support for full task management model. But they process ORDERED
|
||||
commands the same way as SIMPLE commands, i.e. allow free reorder of them before they get executed. That violates SCSI standard
|
||||
and can lead to a data corruption to any application relying on commands order provided by ORDERED attribute.</p>
|
||||
|
||||
<p><A NAME="15"></A> 15. LIO exports the information needed for an RFC 4455 implementation, but requires additional RFC 4455 implementing module.
|
||||
<p><A NAME="13"></A> 13. LIO exports the information needed for an RFC 4455 implementation, but requires additional RFC 4455 implementing module.
|
||||
At the moment, there is no open source implementation of such module.</p>
|
||||
|
||||
<p><A NAME="16"></A> 16. SCSI pass-through mode allows to export your local SCSI-capable device. For instance with it you can share your parallel
|
||||
<p><A NAME="14"></A> 14. SCSI pass-through mode allows to export your local SCSI-capable device. For instance with it you can share your parallel
|
||||
SCSI tape or SATA DVD-RW device to your iSCSI network.</p>
|
||||
|
||||
<p><A NAME="17"></A> 17. STGT and LIO don't emulate all the necessary SCSI host functionality to allow to share SCSI devices
|
||||
<p><A NAME="15"></A> 15. STGT and LIO don't emulate all the necessary SCSI host functionality to allow to share SCSI devices
|
||||
in pass-through mode to several initiators, although LIO has some necessary processing, but not all.
|
||||
They can only pass SCSI commands from initiators to
|
||||
SCSI devices and responses back. This is safe only with a single initiator. This limitation
|
||||
isn't enforced anyhow and both STGT and LIO don't issue any warning about it, so an user will not be notified about this
|
||||
limitation and can quietly corrupt his/her data. You can find more technical information about it
|
||||
<a href="http://www.mail-archive.com/linux-scsi@vger.kernel.org/msg06911.html">here</a>.
|
||||
Also neither STGT, nor LIO in pass-through mode do the necessary sense processing for tape devices to
|
||||
correctly return residual information, so tapes can used with them with limited functionality.</p>
|
||||
Also LIO in pass-through mode doesn't do necessary sense processing for tape devices to
|
||||
correctly return residual information, so tapes can used with it with limited functionality.</p>
|
||||
|
||||
<p><A NAME="18"></A> 18. You can find a proposal how to implement zero-copy FILEIO in SCST on the <a href="contributing.html#ZC_READ">
|
||||
<p><A NAME="16"></A> 16. You can find a proposal how to implement zero-copy FILEIO in SCST on the <a href="contributing.html#ZC_READ">
|
||||
Contributing</a> page.</p>
|
||||
|
||||
<p><A NAME="19"></A> 19. Doesn't need any kernel patch, except in the case, when used with user space backend.</p>
|
||||
<p><A NAME="17"></A> 17. Doesn't need any kernel patch, except in the case, when used with user space backend.</p>
|
||||
|
||||
<p><A NAME="20"></A> 20. Connections and sessions reinstatement is, basically, a kind of Task Management command, because it implies commands aborting.
|
||||
<p><A NAME="18"></A> 18. Connections and sessions reinstatement is, basically, a kind of Task Management command, because it implies commands aborting.
|
||||
So, similarly to the safe task management above, a safe implementation of connections and sessions reinstatement
|
||||
must not accept SCSI commands from new connection/session until all the SCSI commands in
|
||||
being reinstated connection/session get into a state, where they can't affect new commands.</p>
|
||||
|
||||
<p><A NAME="21"></A> 21. "Safe restart" means that after the iSCSI target restart, all the connected initiators will seamlessly restore all existing before
|
||||
<p><A NAME="19"></A> 19. "Safe restart" means that after the iSCSI target restart, all the connected initiators will seamlessly restore all existing before
|
||||
the restart connections. "Not safe" means that, most likely, the connected initiators will fail to restore
|
||||
existing connections with some errors. However, your iSCSI initiator also should be able to handle the safe restart. For instance,
|
||||
old (pre-CentOS/RHEL 5) open-iscsi has problems in this area. But the latest versions do it pretty well.</p>
|
||||
|
||||
<p><A NAME="22"></A> 22. All ALUA states
|
||||
transitioning implemented as empty placeholders, which means this implementation can't be used to build ALUA-based
|
||||
clusters without additional code.</p>
|
||||
<p><A NAME="20"></A> 20. Generic implementation, i.e. not coupled to any particular cluster implementation, which means it is needed additional effort
|
||||
to used with each particular cluster setup.</p>
|
||||
|
||||
</div>
|
||||
</div>
|
||||
|
||||
@@ -36,8 +36,10 @@
|
||||
<div id="main">
|
||||
<h1>SCST Downloads</h1>
|
||||
|
||||
<p>The latest stable released version of SCST core is 2.0.0.1. It requires Linux kernel 2.6.18 or higher.
|
||||
More detail information you could find in its README file.</p>
|
||||
<p>The latest stable released version of SCST core is 2.0.0.1. The latest updates for it
|
||||
you can find it in the SVN branch 2.0.0.x.</p>
|
||||
|
||||
<p>The latest stable pre release version is 2.1-rc1. You can find it in the SVN branch 2.1.0.x.</p>
|
||||
|
||||
<p>You can also download prebuilt SCST modules for
|
||||
<a href="http://linuxsoft.cern.ch/cern/slc5X/x86_64/yum/extras/repoview">Scientific Linux CERN 5</a> (RHEL5-based),
|
||||
|
||||
@@ -151,6 +151,7 @@
|
||||
<p><a href="http://iscsi-scst.sourceforge.net/SCST_Gentoo_HOWTO.txt">Gentoo HOWTO For iSCSI-SCST</a></p>
|
||||
<p><a href="http://alpinelinux.org/wiki/High_performance_SCST_iSCSI_Target_on_Linux_software_Raid" class="readmore">Alpine Linux HOWTO</a></p>
|
||||
<p><a href="qla2x00t-howto.html">HOWTO For QLogic Target Driver</a></p>
|
||||
<p><a href="qla2x00t-howto-debian.html">Ubuntu/Debian HOWTO For QLogic Target Driver</a></p>
|
||||
<p><a href="http://lpfcxxxx.sourceforge.net/HOWTO.lpfc">HOWTO For Emulex lpfc Target Driver</a></p>
|
||||
<p><a href="sgv_cache.html">SCST SGV Cache Description</a></p>
|
||||
<h1>Articles</h1>
|
||||
|
||||
@@ -37,6 +37,7 @@
|
||||
<h1>Comparison</h1>
|
||||
<ul class="sidemenu">
|
||||
<li><a href="comparison.html">Features comparison</a></li>
|
||||
<li><a href="scstvslio.html">SCST vs LIO/TCM</a></li>
|
||||
<li><a href="scstvsstgt.html">SCST vs STGT</a></li>
|
||||
<li><a href="mc_s.html">MC/S vs MPIO</a></li>
|
||||
</ul>
|
||||
|
||||
119
www/scstvslio.html
Normal file
119
www/scstvslio.html
Normal file
@@ -0,0 +1,119 @@
|
||||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||||
<html>
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||||
<meta name="author" content="Daniel Fernandes">
|
||||
<meta name="Robots" content="index,follow">
|
||||
<link rel="stylesheet" href="images/Orange.css" type="text/css">
|
||||
<title>SCST vs LIO/TCM</title>
|
||||
</head>
|
||||
|
||||
<body>
|
||||
<!-- wrap starts here -->
|
||||
<div id="wrap">
|
||||
<div id="header">
|
||||
<div class="logoimg"></div><h1 id="logo"><span class="orange"></span></h1>
|
||||
<h2 id=slogan>Generic SCSI Target Subsystem for Linux</h2>
|
||||
</div>
|
||||
|
||||
<div id="menu">
|
||||
<ul>
|
||||
<li><a href="index.html">Home</a></li>
|
||||
<li><a href="http://www.sourceforge.net/projects/scst">Main</a></li>
|
||||
<li><a href="http://sourceforge.net/news/?group_id=110471">News</a></li>
|
||||
<li><a href="targets.html">Drivers</a></li>
|
||||
<li><a href="downloads.html">Downloads</a></li>
|
||||
<li><a href="contributing.html">Contributing</a></li>
|
||||
<li id="current"><a href="comparison.html">Comparison</a></li>
|
||||
<li><a href="users.html">Users</a></li>
|
||||
<li><a href="solutions.html">Solutions</a></li>
|
||||
</ul>
|
||||
</div>
|
||||
|
||||
<!-- content-wrap starts here -->
|
||||
<div id="content-wrap">
|
||||
<div id="sidebar">
|
||||
<h1>Comparison</h1>
|
||||
<ul class="sidemenu">
|
||||
<li><a href="comparison.html">Features comparison</a></li>
|
||||
<li><a href="scstvslio.html">SCST vs LIO/TCM</a></li>
|
||||
<li><a href="scstvsstgt.html">SCST vs STGT</a></li>
|
||||
<li><a href="mc_s.html">MC/S vs MPIO</a></li>
|
||||
</ul>
|
||||
</div>
|
||||
|
||||
<div id="main">
|
||||
<h1>SCST vs LIO/TCM</h1>
|
||||
<p>LIO, from recently being renamed to TCM, is another independent from SCST implementation
|
||||
of SCSI target framework for Linux. It's started as PyX iSCSI target and then was
|
||||
accommodated to other transports. But it's still in many kinds iSCSI-oriented.
|
||||
You can find an example when people are not happy with it
|
||||
<a href="http://thread.gmane.org/gmane.linux.scsi/65703/focus=66749">here</a>.</p>
|
||||
|
||||
<p>LIO maintainer, Nicholas Bellinger, is very good in building personal relationships and promoting LIO,
|
||||
although often using misleading half, less-then-half and simply deceitful statements
|
||||
about LIO current state, capabilities and future directions as well as about its competitor, SCST.
|
||||
For instance, he setup LIO targets comparison page with obviously wrong statements about SCST, like
|
||||
that it isn't fully zero copy or it isn't a generic target engine (while LIO, of course, is fully
|
||||
zero-copy and fully generic target engine). Any
|
||||
<a href="http://sourceforge.net/mailarchive/message.php?msg_id=21741080">attempts</a>
|
||||
to correct it were simply ignored.</p>
|
||||
|
||||
<p>With those tricks Nicholas Bellinger was capable to attract key Linux kernel developers, and
|
||||
they suddenly changed their opinion about Linux SCSI target subsystem in the opposite direction.
|
||||
They previously asserted that
|
||||
in-kernel SCSI target is the wrong direction, SCSI target must be in the user space, so
|
||||
STGT is what everybody needed. Now their opinion is that SCSI target driver should be in the kernel space
|
||||
and the only target good for them is LIO, doesn't matter that:</p>
|
||||
|
||||
<ol>
|
||||
<li><span>SCST is a lot more mature and advanced</span></li>
|
||||
|
||||
<li><span>SCST from the beginning is a generic SCSI target</span></li>
|
||||
|
||||
<li><span>SCST has a lot more features</span></li>
|
||||
|
||||
<li><span>SCST has better performance</span></li>
|
||||
|
||||
<li><span>SCST has a lot more users</span></li>
|
||||
|
||||
<li><span>SCST has much bigger community</span></li>
|
||||
|
||||
</ol>
|
||||
|
||||
<p>So, rejecting base principles of the Linux kernel community that the best code should win, the worst
|
||||
code was chosen.</p>
|
||||
|
||||
<p>You can find more background behind choosing LIO as the mainline kernel SCSI target
|
||||
subsystem if you read <a href="http://thread.gmane.org/gmane.linux.kernel/1078109/focus=1078310">this thread</a>
|
||||
as well as searching for targets related topics in Linux kernel and Linux SCSI mailing lists.</p>
|
||||
|
||||
<p>Particularly notable is that James Bottomley from the beginning was telling that SCST
|
||||
can't be merged in the mainline kernel, because it doesn't offer a drop in replacement for STGT
|
||||
to avoid having 2 target infrastructures in the kernel at the same time. But, since LIO can't
|
||||
offer user space backend drivers and doesn't have ibmvstgt driver analog, for LIO the drop in replacement wasn't
|
||||
a requirement, so 2.6.38+ kernels successfully have both STGT and LIO.</p>
|
||||
</div>
|
||||
</div>
|
||||
</div>
|
||||
<!-- wrap ends here -->
|
||||
<!-- footer starts here -->
|
||||
<div id="footer">
|
||||
<p>© Copyright 2004-2011 <b><font color="#EC981F">Vladislav Bolkhovitin/SCST Ltd & others.</font></b>
|
||||
Design by: <b><font color="#EC981F">Daniel Fernandes</font></b> </p>
|
||||
</div>
|
||||
<!-- footer ends here -->
|
||||
<!-- Piwik -->
|
||||
<script type="text/javascript">
|
||||
var pkBaseURL = (("https:" == document.location.protocol) ? "https://apps.sourceforge.net/piwik/scst/" : "http://apps.sourceforge.net/piwik/scst/");
|
||||
document.write(unescape("%3Cscript src='" + pkBaseURL + "piwik.js' type='text/javascript'%3E%3C/script%3E"));
|
||||
</script><script type="text/javascript">
|
||||
piwik_action_name = '';
|
||||
piwik_idsite = 1;
|
||||
piwik_url = pkBaseURL + "piwik.php";
|
||||
piwik_log(piwik_action_name, piwik_idsite, piwik_url);
|
||||
</script>
|
||||
<object><noscript><p><img src="http://apps.sourceforge.net/piwik/scst/piwik.php?idsite=1" alt="piwik"></p></noscript></object>
|
||||
<!-- End Piwik Tag -->
|
||||
</body>
|
||||
</html>
|
||||
@@ -37,6 +37,7 @@
|
||||
<h1>Comparison</h1>
|
||||
<ul class="sidemenu">
|
||||
<li><a href="comparison.html">Features comparison</a></li>
|
||||
<li><a href="scstvslio.html">SCST vs LIO/TCM</a></li>
|
||||
<li><a href="scstvsstgt.html">SCST vs STGT</a></li>
|
||||
<li><a href="mc_s.html">MC/S vs MPIO</a></li>
|
||||
</ul>
|
||||
@@ -70,10 +71,8 @@
|
||||
|
||||
</ul>
|
||||
|
||||
<p>Also don't be deceived by the fact that some (small) part of STGT was accepted into the kernel.<br>
|
||||
It doesn't mean that STGT has the "kernel quality". STGT as a whole similarly to any other
|
||||
out-of-kernel-tree project lives on its own, hence has its own quality level, which isn't necessary better, than the
|
||||
quality level of SCST.</p>
|
||||
<p>Time has proved that STGT is too weak to satisfy modern storage requirements. Now it is obsolete and
|
||||
soon going to be removed from the mainline kernel.</p>
|
||||
|
||||
</div>
|
||||
</div>
|
||||
|
||||
Reference in New Issue
Block a user