HP AJ878A - StorageWorks 320 GB Hard Drive Release Note page 6

HP BladeSystem technical resources (white papers and support documents):
go/bladesystem/documentation
HP BladeSystem components:
c-class-components.html
IO Accelerator Documentation:
HP support: http://www.hp.com/support
Linux-Specific information
Linux MD RAID5 performs poorly
The Linux kernel RAID5 implementation performs poorly at high data rates. This must be fixed in the
Linux kernel and is not controlled by HP. Alternatives include using RAID10, or possibly a third-party
RAID stack. The cause of the issue is believed to be that the RAID5 parity calculation is handled by
a single kernel thread, which doesn't match the performance of an array of IO Accelerator drives.
Drivers not installed after updating kernel
When the driver is installed for a specific kernel version and the kernel version is changed for any
reason, the IO Accelerator driver RPM must be reinstalled to work with the new kernel version. The
utilities and firmware RPMs do not have to be reinstalled.
Driver may not autoload in some distributions
When using RHEL4 and SLES10, the driver installation package may not properly configure itself to
be automatically loaded in all run level boot sequences. To check, after you have installed the driver,
run the following command at a shell prompt:
$ chkconfig
You should see:
$ iodrive 0:off 1:on 2:on 3:on 4:on 5:on 6:off
This shows that the driver will load if the server is booted at run levels 1-5. At a minimum, the run
levels at which you would ever use or maintain the IO Accelerator must be enabled. If that's not the
case, run the following commands at a shell prompt (with root privilege):
$ chkconfig --del iodrive
$ chkconfig --add iodrive
$ chkconfig --list | grep iodrive
You should now see the result shown above. If you need further assistance, contact HP Support
/www.hp.com/support.
IO Accelerator Driver is not SLES11 Certified
Loading the driver on SLES11 requires a work-around because the driver is not certified. This
workaround is implemented by the SLES11 installer. If you are doing a manual installation of the
RPMS, in order to load the driver, one of the following is required:
Add --allow-unsupported to the modprobe line used to load the fio-driver module.
6
http://h18004.www1.hp.com/products/blades/components/
http://www.hp.com/go/bladesystem/mezzanines
list | grep iodrive
http://www.hp.com/
http:/