[Linux-cluster] Clustered LVM for storage

Jeff Sturm jeff.sturm at eprize.com
Fri Mar 9 15:55:36 UTC 2012


Sure.   As long as you don't try to make use of any LVM features that require metadata consistency (mirroring, snapshots, online resizing, etc.) you can get by using LVM without clustering.

-Jeff

From: linux-cluster-bounces at redhat.com [mailto:linux-cluster-bounces at redhat.com] On Behalf Of Charles Riley
Sent: Friday, March 09, 2012 8:56 AM
To: linux clustering
Subject: Re: [Linux-cluster] Clustered LVM for storage


We're talking 36TB of storage here..  I've never had much success partitioning an array of that size (and actually being able to use all of the space) without lvm.  But I might give that a try.

Continuing along this line of thought:
If I stop access to the array from all of the servers before I make any changes, I could probably even make use of lvm without clustering.

Charles


On Thu, Mar 8, 2012 at 5:59 PM, Jeff Sturm <jeff.sturm at eprize.com<mailto:jeff.sturm at eprize.com>> wrote:
With aoe you can use old-fashioned disk partitioning.  Just run "parted" (or whatever partitioning tool you choose) and allocate storage for partitions as you see fit.

The benefits of doing this are:  Easier/simpler to setup than cluster suite, and you can still use all the spindles from your aoe target (for example by creating a large RAID-10 array across all disks).

The downside of partitions is they aren't easy to change.  You can add them safely while the storage array is in use, but each host needs to reload the partition table when you're done with changes before the new storage can be used, and that may not happen until you rmmod/modprobe the aoe driver, which you can't do while any partitions are in use, e.g. on mounted file systems.  And resizing partitions is tricky because they are allocated on consecutive sectors.

So if you want the flexibility of adding/removing/modifying volumes at any time, it may be worth the trouble to get Cluster Suite running so you can use CLVM.  If you just want to carve it up once and forget about it, partitioning the array will be the fastest.

-Jeff

From: linux-cluster-bounces at redhat.com<mailto:linux-cluster-bounces at redhat.com> [mailto:linux-cluster-bounces at redhat.com<mailto:linux-cluster-bounces at redhat.com>] On Behalf Of Charles Riley
Sent: Thursday, March 08, 2012 1:59 PM
To: linux cluster
Subject: [Linux-cluster] Clustered LVM for storage

Greetings,

I have an aoe device with a lot of storage in it that I would like to share among four rhel 4 servers.  Each of the servers will mount it's own storage, no data is shared between them.  e.g the servers won't be mounting the same volumes.

I could create four different raid groups on the aoe device and present a different one to each server, but that would waste space.
What I'd rather do is create one big raid group and use clustered lvm to divvy the space between servers.

Is it possible?  Would it be enough to run just the clustered lvm daemon, or would I need to install all of the cluster suite?
Are there other/better options?

Thanks!

Charles





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