topic Re: EMC LUN presented to RHEL 5.3 in Operating System - Linux

EMC LUN presented to RHEL 5.3

Techsystemquery — Wed, 07 Jul 2010 13:23:49 GMT

pvcreate /dev/emcpowerb

above command creates PV but its shows as native disk (/dev/sdab) not as emcpowerb
PV VG Fmt Attr PSize PFree
/dev/emcpowerd lvm2 -- 68.00G 68.00G
/dev/sdab lvm2 -- 68.00G 68.00G
/dev/sdn vg1 lvm2 a- 68.00G 400.00M

/dev/emcpowerd looks fine.

lvm filter is as below

filter = [ "a/.*/" ]

Re: EMC LUN presented to RHEL 5.3

Kapil Jha — Wed, 07 Jul 2010 13:38:29 GMT

where it shows as native disk?
what does powermt display dev=all says....if you have powerpath or
multipath -ll

if u have multi path.

BR,
Kapil+

Re: EMC LUN presented to RHEL 5.3

Techsystemquery — Wed, 07 Jul 2010 13:41:50 GMT

Note : root vg is on local scsi disks

/dev/cciss/c0d0p1 vg0 lvm2 a-
/dev/cciss/c0d0p2 vg0 lvm2 a-

Re: EMC LUN presented to RHEL 5.3

Gerardo Arceri — Wed, 07 Jul 2010 14:38:56 GMT

Hi, you need to modify lvm.conf to exclude sd* devices. Please take a look at the following thread.
http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1432302

Re: EMC LUN presented to RHEL 5.3

Techsystemquery — Wed, 07 Jul 2010 14:47:09 GMT

Gerardo ,

If add filter to remove sd* do it affect the already added vg1 ? DO i need umount filesystem before doing this ?

Re: EMC LUN presented to RHEL 5.3

Gerardo Arceri — Wed, 07 Jul 2010 17:11:17 GMT

No need to unmount the filesystems.
is /dev/sdn also an EMC luns ?
In case it's a local disk you will need to include it in the filter line.

Re: EMC LUN presented to RHEL 5.3

John Guster — Thu, 08 Jul 2010 15:48:43 GMT

With RHEL 5.3 system, you could use DM multipath to manage SAN storage much better than 3rd party software as EMC powerpath. However, if you still stay with PowerPath, you have to modify the mount option in /etc/fstab something like below: defaults,_netdev otherwise system will have issue in booting.
adding the filter in /etc/lvm/lvm.conf should correct the issue.

Re: EMC LUN presented to RHEL 5.3

Steven E. Protter — Thu, 08 Jul 2010 18:38:24 GMT

Shalom,

If you have changed your filter, and powerpath is running you may need to talk to your storage administrator.

I can't give you specifics, however when we first tried to present EMC Symmetrix disk to a Linux system we had issues and the Storage admin had to try a few things before it was recognized.

If its Clarion, the parameters may be a little different. Same thing with Celera.

There are tools for disk detection and they are specific to the fiber card you are using. If you are using Emulex, you need Emulex tools. If you are using Qlogic, you need Qlogic tools.

What I see here however might be solved by the SAN admin.

SEP