[ale] LVM on iscsi for cluster

[Ed Cashin]

For active/passive HA...

It's possible to use non-cluster LVM if only one host at a time
ever activates the logical volume.  In principle that's not hard,
because it's the same as making sure a traditional filesystem
like XFS only gets mounted by one host at a time.  It requires
some deep knowledge of LVM to ensure that things happen
as planned when failover occurs (and not when it doesn't).

However, I've seen so many people get this wrong (same
goes for md) that I never recommend it.  I think studying the
http://www.linux-ha.org/doc/users-guide/users-guide.html
and double checking configurations on the public forums
there might ensure success, though.

On Tue, Jan 25, 2011 at 4:44 PM, Greg Freemyer <greg.freemyer at gmail.com> wrote:
> Sounds like you need Cluster enabled LVM. Or CLVM for short.
>
> http://sourceware.org/cluster/clvm/
>
> fyi: I haven't used it, but I do think it is the typical solution to
> your problem.
>
> Greg
>
> On Tue, Jan 25, 2011 at 1:32 PM, Robert Coggins <ale at cogginsnet.com> wrote:
>> Good day all,
>>
>> I am working on creating an HA cluster for mysql.  Right now I have 2
>> nodes pointing to an iscsi target.  Both nodes see my linux LVM
>> partition as /dev/sdb1.  On node a I did the pvcreate, vgcreate, and
>> lvcreate.  On node a and b I see the pv, vg and lv when doing pvscan,
>> vgscan and lvscan or displays.  However, I can only make the lvm on node
>> a active (using vgchange -ay and lvchange -ay).  however when I try the
>> same on node b I get "Command failed with status code 5" and I do this
>> when the lvm is unavailable on node a.  Any ideas?
>>
>> Robert
>
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-- 
  Ed Cashin <ecashin at noserose.net>
  http://noserose.net/e/
  http://www.coraid.com/