mirror of
https://github.com/SCST-project/scst.git
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Gleb Chesnokov
962d6f1dc1
The generated SRPT documentation still contained commands for the removed /proc/scsi_tgt interface. The comparison page advertised procfs as an SCST option and Debian metadata named deleted procfs sources. Remove these stale references while retaining scstadmin migration support.
68 lines
2.8 KiB
Plaintext
68 lines
2.8 KiB
Plaintext
SCSI RDMA Protocol (SRP) Target driver for Linux
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=================================================
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Configuration
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-------------
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Use ../INSTALL.md and README for current build and SRPT guidance. Configure
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SCST devices, targets and LUNs through the sysfs interface with scstadmin.
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The SRP Target driver is designed to work directly on top of the
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OpenFabrics OFED-1.x software stack (http://www.openfabrics.org) or
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the Infiniband drivers in the Linux kernel tree
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(http://www.kernel.org). The SRP target driver also interfaces with
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the generic SCSI target mid-level driver called SCST
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(http://scst.sourceforge.net).
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On initiator machines you can manually do the following steps:
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1. modprobe ib_srp
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2. ibsrpdm -c (to discover new SRP target)
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3. echo <new target info> > /sys/class/infiniband_srp/srp-mthca0-1/add_target
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4. fdisk -l (will show new discovered scsi disks)
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Example:
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Assume that you use port 1 of first HCA in the system ie. mthca0
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[root@lab104 ~]# ibsrpdm -c -d /dev/infiniband/umad0
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id_ext=0002c90200226cf4,ioc_guid=0002c90200226cf4,
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dgid=fe800000000000000002c90200226cf5,pkey=ffff,service_id=0002c90200226cf4
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[root@lab104 ~]# echo id_ext=0002c90200226cf4,ioc_guid=0002c90200226cf4,
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dgid=fe800000000000000002c90200226cf5,pkey=ffff,service_id=0002c90200226cf4 >
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/sys/class/infiniband_srp/srp-mthca0-1/add_target
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OR
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+ You can edit /etc/infiniband/openib.conf to load srp driver and srp HA daemon
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automatically ie. set SRP_LOAD=yes, and SRPHA_ENABLE=yes
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+ To set up and use high availability feature you need dm-multipath driver
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and multipath tool
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+ Please refer to OFED-1.x SRP's user manual for more in-details instructions
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on how-to enable/use HA feature
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To minimize QUEUE_FULL conditions, you can apply scst_increase_max_tgt_cmds
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patch from SRPT package from http://sourceforge.net/project/showfiles.php?group_id=110471
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Performance notes
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-----------------
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In some cases, for instance working with SSD devices, which consume 100%
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of a single CPU load for data transfers in their internal threads, to
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maximize IOPS it can be needed to assign for those threads dedicated
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CPUs using Linux CPU affinity facilities. No IRQ processing should be
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done on those CPUs. Check that using /proc/interrupts. See taskset
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command and Documentation/core-api/irq/irq-affinity.rst in your kernel's
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source tree for how to assign CPU affinity to tasks and IRQs.
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The reason for that is that processing of coming commands in SIRQ context
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can be done on the same CPUs as SSD devices' threads doing data
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transfers. As the result, those threads won't receive all the CPU power
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and perform worse.
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The ib_srpt thread parameter was removed when its former thread=1 mode
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became unconditional. No module option is needed to select that mode.
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Send questions about this driver to scst-devel@lists.sourceforge.net, CC:
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Vu Pham <vuhuong@mellanox.com> and Bart Van Assche <bvanassche@acm.org>.
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