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git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@9231 d57e44dd-8a1f-0410-8b47-8ef2f437770f
84 lines
2.5 KiB
Plaintext
84 lines
2.5 KiB
Plaintext
User space FILEIO handler
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=========================
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Version 3.5.0, 21 December 2020
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----------------------------
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User space program fileio_tgt uses interface of SCST's scst_user dev
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handler and allows to see how it works in various modes. Fileio_tgt
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provides mostly the same functionality as the kernel space SCST's
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scst_vdisk handler with the only exceptions that it supports O_DIRECT
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mode and doesn't support BLOCKIO one. O_DIRECT mode is basically the
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same as BLOCKIO, but also supports files, so for some loads it could be
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significantly faster, than the regular FILEIO access. All the words
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about BLOCKIO mode from SCST's README file apply to O_DIRECT mode as
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well.
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Installation
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------------
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Make sure you have installed SCST core, if not, see its README file for
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details how to do it.
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Then run "make all install"
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For the best performance make sure you don't have any debug options
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(i.e. lines like "CFLAGS += -DDEBUG" containing "-DDEBUG*" string)
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enabled in the Makefile.
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Usage
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-----
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Load scst_user module using modprobe or insmod, then start fileio_tgt
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program. It can be used as the following:
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fileio_tgt [OPTION] name path
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Where:
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- OPTION - one or several not required options, see below.
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- name - name of the virtual device as it will be seen by SCST and used
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in the subsequent access management using the corresponding SCST interface.
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- path - path to the device file.
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The following options are supported:
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-b or --block=size: block size, must be power of 2 and >=512
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-e or --threads=count: number of threads
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-t or --write_through: write through mode
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-r or --read_only: read only
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-o or --direct: O_DIRECT mode, see above for details
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-n or --nullio: NULLIO mode, see SCST's README file for details
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-c or --nv_cache: NV_CACHE mode, see SCST's README file for details
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-p or --parse=type: parse type, one of "std" (default), "call" or "excpt"
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-f or --on_free=type: on free call type, one of "ignore" (default) or "call"
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-m or --mem_reuse=type: Memory reuse type, one of "all" (default), "read",
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"write" or "none"
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-s or --prio_thread: Use separate thread for mgmt (prio) commands
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-l or --non_blocking: Use non-blocking operations
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Also in the debug builds the following options are supported:
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-d or --debug=level: debug tracing level
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-g or --debug_tm_ignore: turn on DEBUG_TM_IGNORE, one of the task management
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debugging features
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If you don't understand some these options, don't use them, default
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values provide the best performance.
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Vladislav Bolkhovitin <vst@vlnb.net>, http://scst.sourceforge.net
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