On Fri, 11 Dec 2009 08:15:26 +0100 Luca Berra <bluca@xxxxxxxxxx> wrote: > On Thu, Dec 10, 2009 at 12:37:03PM +1100, Neil Brown wrote: > >On Wed, 9 Dec 2009 15:03:11 -0800 > >> 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. > > > _with_ a superblock? or without? Either. > what happens if one node modifies the superblock while the other is > running. Once a RAID0 has been created, there is never any need to modify the superblock, and I'm fairly sure we don't. > > >It might work for RAID1 one day to, but is unlikely to ever work for > >RAID5. > With an external metadata handler i believe it would be possible to > support up to raid1, maybe 10. That is the idea, yes. > > While in similar setups, data protection should be handled by the > storage system, raid 1 has its uses in a failover setup with two sites. > I don't see a real use for raid5/6 in such scenarios. If I had 16 nodes, each with a local device and a fast interconnect, I might want to have a filesystem that spanned all of the devices but survived the failure of any two nodes. Then having a stripe/parity layout across the devices would be useful. However I think the only way to get good performance would be to require that the filesystem does full-stripe writes every time. So I think that would look more like a clusterised ZFS ... but who knows. 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
