On Wed, 9 Dec 2009 15:03:11 -0800 "Patrick J. LoPresti" <lopresti@xxxxxxxxx> 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? For RAID0 or LINEAR, this should work - give it a try. If it doesn't work in some way, let me know and I'll see about fixing it. It might work for RAID1 one day to, but is unlikely to ever work for RAID5. NeilBrown -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
