From: "Heinz J . Mauelshagen" <mauelshagen@sistina.com>
To: linux-lvm@sistina.com
Subject: Re: [linux-lvm] Quorums / VGDAs
Date: Wed Sep 11 05:57:56 2002 [thread overview]
Message-ID: <20020911123312.D26854@sistina.com> (raw)
In-Reply-To: <3D7E4050.B3BEEE@storix.com>; from anthony@storix.com on Tue, Sep 10, 2002 at 11:56:16AM -0700
On Tue, Sep 10, 2002 at 11:56:16AM -0700, Anthony Johnson wrote:
> I'm trying to find information on the availability factors of LVM. As I
> understand it, a quorum is required for a volume group to be available.
> I have some questions in this regard:
>
> 1) What defines a quorum - over 50% of the PVs in the VG, or over 50%
> of the VGDAs?
VG quorum is given in case all of its PVs are available.
> 2) How many VGDAs are stored on each physical volume. From AIX
> experience, this varied depending on the number of PVs in the VG.
In the LVM1 metadata there's allways 1 VGDA on each PV which has internal
redundancy.
With the new LVM2 formats you can have as many VGDA copies as you like.
> 3) If quorum is lost on an active VG, is the entire VG automatically
> varied off?
No, it will stay accessable with the exception of the dead PV(s).
> 4) Can a VG without quorum be forcefully varied on?
With LVM1.1 (see CVS; WARNING: his is interim development code!) and with final
LVM2 later this year, you can activate a VG which has lost quorum.
> 5) Can quorum checking be disabled?
No, but with the above SW you can activate the VG in case there's
at least 1 PV still accessable.
>
> Thanks,
> Anthony
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
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> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html
--
Regards,
Heinz -- The LVM Guy --
*** Software bugs are stupid.
Nevertheless it needs not so stupid people to solve them ***
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Heinz Mauelshagen Sistina Software Inc.
Senior Consultant/Developer Am Sonnenhang 11
56242 Marienrachdorf
Germany
Mauelshagen@Sistina.com +49 2626 141200
FAX 924446
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next prev parent reply other threads:[~2002-09-11 5:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-10 13:54 [linux-lvm] Quorums / VGDAs Anthony Johnson
2002-09-11 5:57 ` Heinz J . Mauelshagen [this message]
2002-09-13 15:31 ` Anthony Johnson
2002-09-16 6:38 ` Heinz J . Mauelshagen
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