User Manual

Rev 2.0-3.0.0
Mellanox Technologies
219
Appendix B: SRP Target Driver
The SRP Target driver is designed to work directly on top of OpenFabrics OFED software stacks
(http://www.openfabrics.org) or InfiniBand drivers in Linux kernel tree (kernel.org). It also inter-
faces with Generic SCSI target mid-level driver - SCST (http://scst.sourceforge.net).
By interfacing with an SCST driver, it is possible to work with and support a lot of IO modes on
real or virtual devices in the back end.
1. scst_vdisk – fileio and blockio modes. This allows turning software raid volumes, LVM vol-
umes, IDE disks, block devices and normal files into SRP luns
2. NULLIO mode allows measuring the performance without sending IOs to real devices
B.1 Prerequisites and Installation
1. SRP targer is part of the OpenFabrics OFED software stacks. Use the latest OFED distribu-
tion package to install SRP target.
2. Download and install the SCST driver. The supported version is 1.0.1.1.
a. Download scst-1.0.1.1.tar.gz from http://scst.sourceforge.net/downloads.html
b. Untar scst-1.0.1.1
c. Install scst-1.0.1.1 as follows:
B.2 How-to Run
A. On an SRP Target machine:
1. Please refer to SCST's README for loading scst driver and its dev_handlers drivers
(scst_vdisk block or file IO mode, nullio, ...)
On distribution default kernels you can run scst_vdisk blockio mode to obtain good
performance.
$ tar zxvf scst-1.0.1.1.tar.gz
$ cd scst-1.0.1.1
$ make && make install
Regardless of the mode, you always need to have lun 0 in any group's device list.
Then you can have any lun number following lun 0 (it is not required to have the lun
numbers in ascending order except that the first lun must always be 0).
Setting SRPT_LOAD=yes in /etc/infiniband/openib.conf is not enough as it only loads
the ib_srpt module but does not load scst not its dev_handlers.