topic Re: Forcing LVM (RH4-ES) to see a BIGGER LUN Size in Operating System - Linux

Forcing LVM (RH4-ES) to see a BIGGER LUN Size

NIGEL WHITE_2 — Thu, 18 Oct 2007 05:08:19 GMT

Hello,

Here's my issue.

I have a Volume group which consists of one 100G LUN via a NetAPP SAN Filer. I also have a logical volume of 50g via this volume Group mounted with live data.
I want to be able to resize the 100G LUN to 120G on the SAN Filer and then force LVM to see the extra 20G without having to umount the volume and mess about exporting data and rebuilding the Volume .......

Is there a way of shaking-up LVM to see the extra 20G (extents)? I would use Snapdrive (NetAPP software) but each snapdrive requires a licence and it would be nice to do this when required with my VMware RedHat Servers.

any LVM GURU's out there that know a trick or too with LVM2?

Regards
Nigel

Re: Forcing LVM (RH4-ES) to see a BIGGER LUN Size

Stuart Browne — Thu, 18 Oct 2007 05:12:39 GMT

You should just be able to add the extra extents, using 'pvresize /dev/sdxx'.

You can use the '-t' flag to "test" prior to doing any action.

Once resized, you should then be able to reize your volume groups.

At worst, after extending the LUN, you may need to 'partprobe'.

Re: Forcing LVM (RH4-ES) to see a BIGGER LUN Size

Ivan Ferreira — Thu, 18 Oct 2007 07:48:08 GMT

Red Hat provides the pvresize command. But probably, would be better if you create a new disk and present it to the host, and add the disk to the same volume group.

See also the attached file.

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Re: Forcing LVM (RH4-ES) to see a BIGGER LUN Size

Steven E. Protter — Thu, 18 Oct 2007 08:42:49 GMT

Shalom Nigel,

Forcing software to do anything usually results in bad outcomes.

I would suggest re-creating the volume group with bigger extents -s or less physical volumes -p 10 in order to get the results you desire.

SEP

Re: Forcing LVM (RH4-ES) to see a BIGGER LUN Size

NIGEL WHITE_2 — Thu, 18 Oct 2007 09:20:05 GMT

Normally I would just present a new lun and just add it to the volume group. But now I have a Netapp SAN for storage, I can use a peice of software called snapdrive that's surposed to interact with LVM when a LUN is resized. This is a licenced peice of software, so I just wanted to know if it could be done without snapdrive for my Virtual Redhat servers??

God knows what snapdrive is doing to LVM? It must plugin to LVM and get it to do things it's not surposed to do???

Never mind.

Doe's anyone else on this forum use NetApp Storage with Snapdrive for UNIX/LINUX?

R.
Nigel