User Manual

Rev 2.1-1.0.6
Mellanox Technologies
235
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 r
eal 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, ...)
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).
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
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.