topic Re: Multipathing on RHEL4 in Operating System - Linux

Multipathing on RHEL4

Eric van Dijken — Tue, 08 Mar 2005 08:48:18 GMT

Hi,

I am using RHEL4 on HP BL20p G3 blades and am trying to get a EVA 5000 vdisk running on it.

I now have multipath'ing from the Qlogic driver. Persistent binding with Udev. Which gives me 4 scsi devices for 1 EVA vdisk.

Which brings me to my problem, i only want/need 1 device to be useable. Not 4 (of which 2 are not even useable, as those paths aren't active)

How do i get to a devicename, which i can use. But will stay available even when one of my the SAN paths become unavailable?

ps: HP SecurePath or EMC Powerpath aren't an option.

Re: Multipathing on RHEL4

Steven E. Protter — Tue, 08 Mar 2005 10:02:27 GMT

Before you upgrade to RHEL4.

Wait for HP to come out with full driver support. They usually take a few months to certify and work the kinks out.

The old drivers may work, and you may wish to experiment with a non-production server.

In practice, you will probably need to wait a while.

SEP

Re: Multipathing on RHEL4

Eric van Dijken — Wed, 09 Mar 2005 01:23:55 GMT

The drivers are not the problem. Together with the Proliant Support Pack 7.21, it works just as well (so far and in a non-production env.) as the previous RHEL3 version.

But the time we plan to take RHEL4 in production, it will be rock solid.

But i want to use SAN storage. And the 4 paths to my one Vdisk confuses me a bit.

I could try to use "devlabel", but that only works during boot time. Not real-time (i think).

What i wouls really like to have is just 1 scsi device. And let the kernel (or something else) worry about which path is active.

Re: Multipathing on RHEL4

Serviceguard for Linux — Wed, 09 Mar 2005 02:02:04 GMT

While it may not be fully supported yet, the QLogic driver should have multipathing - but I don't think it is enabled by default. Once enabled, your 4 LUNs will collapse to 1. Look over the existing docs on the HP site - or the QLogic site, to see what parameter needs to be set to turn on multipathing (can't remember off the top of my head :) )

Re: Multipathing on RHEL4

Uwe Zessin — Wed, 09 Mar 2005 03:05:22 GMT

The manual is here:

http://h20000.www2.hp.com/bizsupport/TechSupport/DocumentIndex.jsp?contentType=SupportManual&locale=en_US&docIndexId=179911&taskId=120&prodTypeId=12169&prodSeriesId=421487

Re: Multipathing on RHEL4

Eric van Dijken — Wed, 09 Mar 2005 03:06:18 GMT

I tried this:

Added this line to /etc/modprobe.conf
options qla2xxx ql2xfailover=1 qlport_down_retry=3 qlogin_retry_count=30 ql2xmaxqdepth=16

But after a "modprobe qla2xxx" this was the result:
qla2xxx: Unknown parameter `ql2xfailover'
QLogic Fibre Channel HBA Driver (f8884000)

btw: This is using the default default RHEL4 2.6.9-5.ELsmp kernel.

Re: Multipathing on RHEL4

Eric van Dijken — Wed, 09 Mar 2005 05:37:50 GMT

I tried using the Qlogic driver, but that also failed:

# ./INSTALL -f
Installing hp_qla2x00src RPM...

error: Failed dependencies:
kernel-source is needed by hp_qla2x00src-8.00.00-22.noarch

Installing fibreutils...

Preparing... ########################################### [100%]
1:fibreutils ########################################### [100%]

So i tried installing kernel-2.6.9-5.0.3.EL.src.rpm, but that did not produce a kernel-source (no big supprise)

Re: Multipathing on RHEL4

Jorge Zacarias_1 — Thu, 09 Feb 2006 16:14:54 GMT

Hi Eric,

Did you resolved your problem with the EVA vdisk?. I have a RHEL4 and EVA3000 with 1 vdisk presented to this host. I see 2 scsi devices.

Thanks in advance
Jorge Zacarias