[Ocfs2-users] Combining OCFS2 with Linux software RAID-0?
Sunil Mushran
sunil.mushran at oracle.com
Mon Dec 14 10:20:52 PST 2009
That's old.
sles11 has added the pacemaker cluster stack that works with clvm.
Luis Freitas wrote:
> Brian,
>
> Hmm, I was not aware of this. Seems Novel uses other volume
> manager, called EVMS, not CLVM (?).
>
> From:
> http://wiki.novell.com/index.php/Linux_Data_Management
>
>
>
> Some Open Source OCFS2 Features
>
> Oracle Linux Certification matrix
> <http://www.novell.com/products/server/oracle/matrix.html>
> OCFS2 project web site <http://oss.oracle.com/projects/ocfs2/>
> OCFS2 Development Roadmap <http://oss.oracle.com/osswiki/OCFS2/Roadmap>
> Oracle Cluster File System v2 (OCFS2) is an open source cluster
> management and
> ....
>
> * No exclusive write lock capability yet (now every lock request
> returns: successful). This feature is candidate for SLE10 SP2
> (Q1 2008).
> * OCFS2 on top of a software mirror is not supported yet
> * *Can be managed by EVMS *
>
> *....*
>
> * OCFS2 offers integration with heartbeat2. Heartbeat2 offers a
> Resource Agent 'md group take over'. (which enables fail-over of
> host based mirroring of SAN volumes), but OCFS2 on top of a
> software mirror is not supported.
>
> ...
>
> Best Regards,
> Luis Freitas
>
> --- On *Fri, 12/11/09, Brian Kroth /<bpkroth at gmail.com>/* wrote:
>
>
> From: Brian Kroth <bpkroth at gmail.com>
> Subject: Re: [Ocfs2-users] Combining OCFS2 with Linux software RAID-0?
> To: "Luis Freitas" <lfreitas34 at yahoo.com>
> Cc: "Patrick J. LoPresti" <lopresti at gmail.com>,
> ocfs2-users at oss.oracle.com
> Date: Friday, December 11, 2009, 2:09 PM
>
> Luis Freitas <lfreitas34 at yahoo.com
> <http://us.mc514.mail.yahoo.com/mc/compose?to=lfreitas34@yahoo.com>>
> 2009-12-11 05:40:
> > Patrick,
> >
> > Depending on what you are using, you could use the volume manager
> > to do the striping, but you need to use CLVM. So if you can,
> go for
> > Heartbeat2+CLVM+OCFS2, all integrated.
> >
> > Not sure but I think Heartbeat2+OCFS2 is only available on the
> > vanilla kernels, not on the enterprise ones. Maybe Suse has
> > support, I don't know, you will have to check.
> >
> > Best Regards,
> > Luis Freitas
>
> Just to elaborate on these comments. Last time I checked CLVM
> required
> the openais/cman cluster stack, which neither heartbeat nor ocfs2 use
> (by default). The userspace stack option for ocfs2 in recent mainline
> kernels added support for the openais stack and pacemaker is
> required to
> make heartbeat work with that rather than use it's own cluster stack.
>
> Now, you can do an basic LVM linear span, concatenation, or
> whatever you
> want to call it without any cluster stack, so long as it's not striped
> and so long as you heed Sunil's warning about fat fingering changes to
> the thing while more than one host is using it.
>
> That means that if you want to add another LUN to the span you
> can't do
> it on the fly. You have to do something like this:
>
> # On all nodes:
> umount /ocfs2
>
> # On all nodes but one:
> vgchange -an ocfs2span
> # Or, to be extra safe:
> halt -p
>
> # On the remaining node:
> vgextend ocfs2span /dev/newlun
> lvextend -l+100%FREE /dev/mapper/ocfs2span-lv
> tunefs.ocfs2 -S /dev/mapper/ocfs2span-lv
>
> # You might actually need the fs mounted for that last bit, I forget.
> # Probably a fsck somewhere in there would be wise as well.
>
> # Bring the other nodes back up.
>
> Brian
>
> > --- On Wed, 12/9/09, Patrick J. LoPresti <lopresti at gmail.com
> <http://us.mc514.mail.yahoo.com/mc/compose?to=lopresti@gmail.com>>
> wrote:
> >
> > From: Patrick J. LoPresti <lopresti at gmail.com
> <http://us.mc514.mail.yahoo.com/mc/compose?to=lopresti@gmail.com>>
> > Subject: [Ocfs2-users] Combining OCFS2 with Linux software RAID-0?
> > To: ocfs2-users at oss.oracle.com
> <http://us.mc514.mail.yahoo.com/mc/compose?to=ocfs2-users@oss.oracle.com>,
> linux-raid at vger.kernel.org
> <http://us.mc514.mail.yahoo.com/mc/compose?to=linux-raid@vger.kernel.org>
> > Date: Wednesday, December 9, 2009, 9:03 PM
> >
> > Is it possible to run an OCFS2 file system on top of Linux
> software RAID?
> >
> > Here is my situation. I have four identical disk chassis that
> perform
> > hardware RAID internally. Each chassis has a pair of fiber
> channel
> > ports, and I can assign the same LUN to both ports. I want to
> connect
> > all of these chassis to two Linux systems. I want the two Linux
> > systems to share a file system that is striped across all four
> chassis
> > for performance.
> >
> > I know I can use software RAID (mdadm) to do RAID-0 striping
> across
> > the four chassis on a single machine; I have tried this, it works
> > fine, and the performance is tremendous. I also know I can
> use OCFS2
> > to create a single filesystem on a single chassis that is shared
> > between my two Linux systems. What I want is to combine these two
> > things.
> >
> > Suse's documentation
> > ([1]http://www.novell.com/documentation/sles11/stor_admin/?page=/documentation/sles11/stor_admin/data/raidyast.html)
> > says:
> >
> > "IMPORTANT:Software RAID is not supported underneath clustered
> file
> > systems such as OCFS2, because RAID does not support concurrent
> > activation. If you want RAID for OCFS2, you need the RAID to be
> > handled by the storage subsystem."
> >
> > Because my disk chassis already perform hardware RAID-5, I
> only need
> > Linux to do the striping (RAID-0) in software. So for me,
> there is no
> > issue about "which node should rebuild the RAID" etc. I
> understand
> > that Linux md stores meta-data on the partitions and is not
> cluster
> > aware, but will this create problems for OCFS2 even if it is
> just RAID
> > 0?
> >
> > Has anybody tried something like this? Are there alternative
> RAID-0
> > solutions for Linux that would be expected to work?
> >
> > Thank you.
> >
> > - Pat
> >
> > _______________________________________________
> > Ocfs2-users mailing list
> > [2]Ocfs2-users at oss.oracle.com
> <http://us.mc514.mail.yahoo.com/mc/compose?to=Ocfs2-users@oss.oracle.com>
> > [3]http://oss.oracle.com/mailman/listinfo/ocfs2-users
> >
> > References
> >
> > Visible links
> > 1.
> http://www.novell.com/documentation/sles11/stor_admin/?page=/documentation/sles11/stor_admin/data/raidyast.html
> > 2. file:///mc/compose?to=Ocfs2-users@oss.oracle.com
> <http://us.mc514.mail.yahoo.com/mc/compose?to=Ocfs2-users@oss.oracle.com>
> > 3. http://oss.oracle.com/mailman/listinfo/ocfs2-users
>
> > _______________________________________________
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>
>
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