topic Re: DM-Multipath & Friendly Names in Operating System - Linux

DM-Multipath & Friendly Names

Jorge Fabregas — Wed, 18 May 2011 14:59:33 GMT

Hello everyone,

I'm configuring a RHEL4 system in order to access our SAN disks (XP storage-array). So far, so good. The only problem I'm having is that, after a reboot, the multipath devices are created using their WWID instead of the friendly "alias". I properly configured this in the /etc/multipath.conf file by means of:

"user_friendly_names yes"

The only way to make it work after a reboot is by creating "multipath" entries under the "multipaths" section...but I have to do that for EACH of the disks.

Does anyone knows why wouldn't "user_friendly_names" work?

Thanks,
Jorge

Re: DM-Multipath & Friendly Names

Zinky — Wed, 18 May 2011 15:16:41 GMT

RHEL5 here and we also do a lot of alias'ing in our multipath.conf file's "multipaths{}" section. No way around that if you want your SAN Disks to be easily identifiable for whatever needs you may have.

For our very large systems, we script creating the "multipaths{}" block.

We've also adopted certain standard naming conventions for multipath alias names:

/dev/mapper/XP_SAPMASTER_ASM_DATA001
/dev/mapper/NTAP_SAPDSS_ASM_DATA001
/dev/mapper/EVA_SAPMTEST_ASM_DATA001
...
.....

Works beautifully.

Re: DM-Multipath & Friendly Names

Matti_Kurkela — Thu, 19 May 2011 05:42:18 GMT

On RHEL4 & 5, if your /var/lib/multipath/bindings file is not on the root filesystem (e.g. if you have /var as a separate filesystem), and you're using "user_friendly_names yes", it's very important that you configure an alternate location for the bindings file somewhere within the root filesystem.

The recommended way is to create a directory named /etc/multipath, move the bindings file there and specify the new location in multipath.conf as:

bindings_file /etc/multipath/bindings

See:
https://access.redhat.com/kb/docs/DOC-17650
(RedHat Network access required)

MK

Re: DM-Multipath & Friendly Names

Jorge Fabregas — Thu, 19 May 2011 20:51:52 GMT

Thank you guys for the suggestions. It turned out to be the version I was using. I upgraded to the lastest device-mapper-multipath package (for RHEL4) and it worked properly.

Thanks,
Jorge