drbd-user March 2010 archive
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drbd-user: Re: [DRBD-user] Detection of Logical Volume on nested

Re: [DRBD-user] Detection of Logical Volume on nested LVM

From: Lars Ellenberg <lars.ellenberg_at_nospam>
Date: Tue Mar 09 2010 - 10:22:52 GMT
To: drbd-user@lists.linbit.com

On Tue, Mar 09, 2010 at 10:59:54AM +0100, Olivier LAMBERT wrote:
> I've got your point. I know my first message is long and maybe
> complicated. It seems you "jump" some lines. It's not "nested" LVM as
> described in the doc (because I RTFM before try to ask help).
>
> My problem is not located on DRBD hosts. I've run some test, and I can
> really simplify the example. Please, read this, I think it's clear now
> :
> Let's say I export a simple physical volume with DRBD. So, NO LVM in
> DRBD, just replicate "/dev/sdb" for example, and export it
> (/dev/drbd0) on each DRBD host with iSCSI.
>
> So, on ALL my clients (connected iSCSI), I saw with "fdisk -l" :
> Disk /dev/sdb: 2998.8 GB, 2998869356544 bytes
>
> So, my CLIENT1 connected to DRBD1, decide to create a volume group and
> a logical volume.
> Despite all my efforts (vgscan, pvscan, lvscan), CLIENT2 connected to
> replicated DRBD2, cannot see anything ! No VG, no LV ! Nothing !
>
> But, if I decide to do that on DRBD2 :
> drbdadm disconnect ressource && drbdadm connect ressource
>
> Just after THIS, I can see all the stuff I've created on CLIENT1.
>
> So, it's NOT a question of LVM on DRBD, because in this case, I don't
> use it anymore. I can undestand if LVM data's on client are not
> replicated on each DRBD hosts, but WHY it works if I
> disconnect/reconnect these two ? It doesn't have any sense to me....

Does the keyword "cache coherence" help?

-- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com DRBD® and LINBIT® are registered trademarks of LINBIT, Austria. __ please don't Cc me, but send to list -- I'm subscribed _______________________________________________ drbd-user mailing list drbd-user@lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user