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Signed-off-by: Bart Van Assche <bvanassche@acm.org> git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@5316 d57e44dd-8a1f-0410-8b47-8ef2f437770f
101 lines
4.4 KiB
Plaintext
101 lines
4.4 KiB
Plaintext
IBM Virtual SCSI Target (ibmvstgt)
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==================================
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Introduction
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------------
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The virtual SCSI (VSCSI) protocol as defined in [2] is a protocol that allows
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one logical partition (LPAR) to access SCSI targets provided by another LPAR.
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The LPAR that provides one or more SCSI targets is called the VIO server or
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VIOS. The ibmvstgt driver is a VIOS driver that makes it possible to access
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exported target devices via the VSCSI protocol.
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Setup
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-----
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After having configured the LPARs, boot the LPARs and load the ibmvstgt kernel
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module in the VIOS. After the target driver has been loaded, verify that a
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message similar to the following appears in the initiator kernel log:
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ibmvscsi 30000028: partner initialized
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ibmvscsi 30000028: host srp version: 16.a, host partition VIOS3-P6 (40), OS 2, max io 67108864
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ibmvscsi 30000028: sent SRP login
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ibmvscsi 30000028: SRP_LOGIN succeeded
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In the above log messages, the number 30000028 refers to the VIOS. The last
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two digits, 0x28, refer to the VIOS partition number (0x28 = 40).
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The next step is to decide which SCSI devices to export. Here is an example of
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a configuration in which 16 RAM disks have been exported (see also [1] for
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more information):
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# ls /sys/kernel/scst_tgt/devices
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2:0:0:0 ram000 ram001 ram002 ram003 ram004 ram005 ram006 ram007
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ram008 ram009 ram010 ram011 ram012 ram013 ram014 ram015
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Next, set the vendor ID, product ID etc. fields via sysfs. These fields
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must be set to the following values to allow AIX initiators to recognize
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SCST devices:
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* The Vendor ID (t10_vend_id) must be set to "IBM".
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* The Product ID (prod_id) must be set either to "VDASD blkdev" for SCSI disks
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or "VOPTA blkdev" for a SCSI CD-ROM.
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* The Product Revision Level (prod_rev_lvl) must be set to "0001".
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* The Vendor Specific Information in the INQUIRY response (inq_vend_specific)
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must be set to the serial number. The serial number is available in the
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"usn" sysfs attribute.
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After this step a LUN has to be assigned to each exported SCSI device. Some
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non-Linux initiator operating systems only accept LUN numbes that are
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multiples of 256 and require that the LUN addressing method is used.
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Assigning LUN numbers is possible e.g. as follows:
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lun=0
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for name in ram000 ram001 ram002 ram003 ram004 ram005 ram006 ram007 \
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ram008 ram009 ram010 ram011 ram012 ram013 ram014 ram015
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do
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lun=$((lun+256))
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echo "add $name $lun" \
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>/sys/kernel/scst_tgt/targets/ibmvstgt/ibmvstgt_target_0/luns/mgmt
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done
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echo 1 >/sys/kernel/scst_tgt/targets/ibmvstgt/ibmvstgt_target_0/enabled
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The result of the above commands will be as follows:
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# cat /sys/kernel/scst_tgt/targets/ibmvstgt/ibmvstgt_target_0/addr_method
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LUN
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# ls /sys/kernel/scst_tgt/targets/ibmvstgt/ibmvstgt_target_0/luns
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256 512 768 1024 1280 1536 1792 2048 2304 2560 2816 3072 3328 3584 3840 4096
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mgmt
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# cat /sys/kernel/scst_tgt/targets/ibmvstgt/ibmvstgt_target_0/enabled
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1
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After SCST has been configured, make the new configuration available to the
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initiator by rescanning the SCSI bus, e.g. as follows:
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# rescan-scsi-bus --hosts=2 --ids=0-31
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# lsscsi 2:
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[2:0:1:0] disk IBM VDASD blkdev 0001 /dev/sdb
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[2:0:2:0] disk IBM VDASD blkdev 0001 /dev/sdc
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[2:0:3:0] disk IBM VDASD blkdev 0001 /dev/sdd
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[2:0:4:0] disk IBM VDASD blkdev 0001 /dev/sde
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[2:0:5:0] disk IBM VDASD blkdev 0001 /dev/sdf
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[2:0:6:0] disk IBM VDASD blkdev 0001 /dev/sdg
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[2:0:7:0] disk IBM VDASD blkdev 0001 /dev/sdh
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[2:0:8:0] disk IBM VDASD blkdev 0001 /dev/sdi
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[2:0:9:0] disk IBM VDASD blkdev 0001 /dev/sdj
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[2:0:10:0] disk IBM VDASD blkdev 0001 /dev/sdk
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[2:0:11:0] disk IBM VDASD blkdev 0001 /dev/sdl
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[2:0:12:0] disk IBM VDASD blkdev 0001 /dev/sdm
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[2:0:13:0] disk IBM VDASD blkdev 0001 /dev/sdn
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[2:0:14:0] disk IBM VDASD blkdev 0001 /dev/sdo
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[2:0:15:0] disk IBM VDASD blkdev 0001 /dev/sdp
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[2:0:16:0] disk IBM VDASD blkdev 0001 /dev/sdq
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References
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----------
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[1] SCST Configuration Interface, Documentation/scst/README.scst.
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[2] Power.org Standard for Power Architecture Platform Requirements (PAPR)
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(Workstation, Server), Version 2.4, December 7, 2009, http://www.power.org.
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[3] Virtual I/O (VIO) and Virtualization, IBM Developerworks, 2010,
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http://www.ibm.com/developerworks/wikis/display/virtualization/VIO.
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