From: Mark Lamport (lamport@KCMETRO.CC.MO.US)
Date: Wed Nov 06 2002 - 09:00:01 EST
The volume group consists of 2 disks and when one of the disks went bad
because it was mirrorred, the file systems on that volume group stayed
available. When I unmirrorred the bad disk I had to perform a migratepv to
move the jfslog as it was on the bad disk. I want to make sure if another
disk goes bad in this volume group, the system stays up. Will it with
quorum set to 1? What command sets the quorum? Should I put a jfslog on
both disks or can I mirror the jfslog? I believe before the problem quorum
was set to 2 and disk1, the initial disk, went bad.
thanks.
----- Original Message -----
From: "Green, Simon" <SGreen@KRAFTEUROPE.COM>
Newsgroups: bit.listserv.aix-l
To: <aix-l@Princeton.EDU>
Sent: Wednesday, November 06, 2002 7:14 AM
Subject: Re: Quorum after replacing bad disk
> For a mirrored VG you probably ought to have Quorum set to 1, (i.e. Off).
>
> If quorum is on, then you need more than half of the disks available for
the
> VG to stay online. Consider an SSA set-up, with two 7133 drawers; LVs are
> mirrored across the drawers. That way, if one of the drawers fails you've
> still got a good copy of your data. However, with quorum on the VG will
go
> offline because you have only half of the disks available, not more than
> half.
>
> If your VG only has two disks, things are a little bit odd. Quorum
actually
> relies on the number of VGDAs (Volume Group Descriptor Areas) available.
> For a large VG there's one on each disk. With a single disk VG there are
> two VGDAs on the disk. For a two-disk VG there are two VGDAs on the first
> disk and one on the second. So with a quorum of two, (the default), if
disk
> two fails the VG stays online; if disk one fails the VG goes offline.
>
> Simon Green
> Philip Morris ITSC Europe
>
> AIX-L Archive at http://marc.theaimsgroup.com/?l=aix-l&r=1&w=2
> AIX FAQ at http://www.faqs.org/faqs/aix-faq/
>
> N.B. Unsolicited email from vendors will seldom be appreciated.
>
> > -----Original Message-----
> > From: Mark Lamport [mailto:lamport@KCMETRO.CC.MO.US]
> > Sent: 06 November 2002 12:27
> > To: aix-l@Princeton.EDU
> > Subject: Quorum after replacing bad disk
> >
> >
> > I had a mirrorred internal disk for a non rootvg volume group go bad
> > yesterday. I unmirrored/reducedvg/remdev and then installed
> > new disk and
> > extendvg/mirrorvg.
> > Everything went fine but when I mirrored I got a message about
> > varyoffvg/varyonvg which I could not do because we were still
> > running those
> > file systems and I could not unmount. This morning I unmounted and
> > performed a syncvg varyoffvg varyonvg and everything worked
> > but I noticed
> > quorum is set at 1 when I believe it should be at 2. How do I set the
> > quorum back to 2?
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