[Ocfs2-users] OCFS2 and LVM2

[Alexei_Roudnev]

You must understand how LVM2 works. It is all STATIC system, so it ALWAYS
can be used in cluster until you don't change metadata. Think about LVM as
about partitions on the disk - you can use partitions with OCFS, so you can
use LVM with OCFS (but you can't change partitions online).

You can create LVM2 volumes using one node, then restart other nodes (and
let them to scan disks) and they will see these volume(s). Then you can use
it as you wish.
But to change volumes, you will:
- stop all nodes but one
- update LVM2 volume on this node
- start other nodes

So, you CAN use LVM2 but you CAN NOT change metadata online while cluster
have more than 1 running node (running node - running OS, stopping OCFS is
not enough).

PS. You don't need to create volumes on a few nodes. What you must do is to
create volumes on ONE node and run vgscan or (boot.lvm start) on all other
nods (so they recognize your volumes).

I recommend to look onto EVMS integrated with OCFSv2 (by SuSe), as a
possible alternative.

----- Original Message ----- 
From: "Gerry Reno" <greno at verizon.net>
To: <Ocfs2-users at oss.oracle.com>
Sent: Sunday, February 25, 2007 3:13 PM
Subject: [Ocfs2-users] OCFS2 and LVM2


> I've been reading a number of OCFS2 posts  from the last year regarding
> the use of OCFS2 over LVM2 and most of them say you cannot do this with
> some saying perhaps with caution.  So my questions are:
>
> Where does this now stand, is there a roadmap to supporting this?
>
> Is there some LVM2 metadata management tool being developed for OCFS2
> similar to lvm2-cluster for GFS?
>
> Is it possible to use OCFS2 over LVM2 today reliably but with some
> limitation?
>   (what I'm thinking is that you could create identical Volume Groups on
> each cluster member and then never modify them - at least not
> dynamically until some new tool is released that would sync metadata and
> permit modification; you could perhaps bring the cluster down and
> statically modify the volume groups on each cluster member in an
> identical manner and then restart the cluster).
>
> Anything else of interest with regard to using OCFS2 over LVM2?
>
>
>
>
>
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