[Ocfs2-users] Combining OCFS2 with Linux software RAID-0?

[Sunil Mushran]

It should work. All ocfs2 needs is a stable shared storage that
is consistent across all nodes all the time.

Patrick J. LoPresti wrote:
> 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
> (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
>
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