topic Re: Fibre Channel Enablement Kit for RHEL 5.6 in Operating System - Linux

Fibre Channel Enablement Kit for RHEL 5.6

Rob Leadbeater — Tue, 29 Mar 2011 08:16:12 GMT

Hi,

Just installed my first RHEL 5.6 system on a HP BL460c G6, and notice that the fibreutils package no longer gets installed by the ProLiant Support Pack with RHEL >= v5.3

A quick Google around suggests that I can install the Fibre Channel Enablement Kit which will give me things like hp_rescan, however the download link here:

http://h20000.www2.hp.com/bizsupport/TechSupport/SoftwareDescription.jsp?lang=en&cc=us&prodTypeId=329290&prodSeriesId=1844100&swItem=co-82357-1&prodNameId=1844101&swEnvOID=4004&swLang=8&taskId=135&mode=3

only mentions RHEL up to 5.5.

Anybody know if there are any issues with it on RHEL 5.6 ?

Regards,

Rob

Re: Fibre Channel Enablement Kit for RHEL 5.6

Matti_Kurkela — Tue, 29 Mar 2011 12:10:08 GMT

The Release Notes for the Fibre Channel Enablement Kit you linked include this note:
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NOTE: Starting with RHEL 5 U3, and SLES 11 Fibre Channel HBAs and mezzanine cards are supported by Red Hat and Novell in-box drivers (included in the OS distribution), and multipath failover is handled by Device Mapper.
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The "hp_rescan" utility is a perl script. The actual scanning is done in the RescanInstance function, which assembles a shell command like this:

echo "- - -" > /sys/class/scsi_host//scan

...and executes it using the system() function. This isn't too hard to do manually :-)
The rest of the script concerns itself with finding the FC HBAs and identifying their SCSI host numbers. That isn't too hard to do manually either: run "lsscsi -H -v" and cross-reference with the "lspci" output if necessary.

RedHat has published an Online Storage Reconfiguration Guide:

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/5/html/Online_Storage_Reconfiguration_Guide/index.html

Its Chapter 9 ("Scanning Storage Interconnects") is appropriate for your case.

It turns out RHEL 5.4 and later include /usr/bin/rescan-scsi-bus.sh script for the same purpose as HP's hp_rescan. RedHat's script can also optionally issue FibreChannel LIPs (essentially HBA resets); hp_rescan cannot do that.

"adapter_info" is a script that seems to only read various HBA-related values from the /sys filesystem and present them in more human-readable form. You could very likely copy this script to future RHEL 5.x and maybe even 6.x systems with no issues, if you like.

The functionality of the other Fibre Channel Enablement Kit commands (scsi_info, lssd, lssg) is duplicated by RHEL 5.x standard utilities lsscsi and scsi_id. "lsscsi" is in its own RPM and will not be installed by default: you must explicitly choose to install it. "scsi_id" is part of the device-mapper-multipath package.

MK

Re: Fibre Channel Enablement Kit for RHEL 5.6

Rob Leadbeater — Tue, 29 Mar 2011 12:35:08 GMT

Thanks Matti - very useful.

I'd been reading through the Red Hat guide you linked to, but hadn't got to chapter 9 yet !

One thing I have just discovered is that the rescan-scsi-bus.sh script is also not installed by default. It's included within the sg3_utils RPM.

Kind regards,

Rob