Robert, > PT> You really need some level of redundancy if you're using HW raid. > PT> Using plain stripes is downright dangerous. 0+1 vs 1+0 and all > PT> that. Seems to me that the simplest way to go is to use zfs to mirror > PT> HW raid5, preferably with the HW raid5 LUNs being completely > PT> independent disks attached to completely independent controllers > PT> with no components or datapaths in common. > > well, it will give you less than half your raw storage. > Due to costs I belive in most cases it won't be acceptable. > People are using raid-5 mostly due to costs and you are proposing > something worse (in terms of available logical storage) than > mirroring.
I realise that, but the question was about what combination of ZFS redundancy and HW-raid redundancy made sense. My point was that putting no redundancy at all at the HW-raid layer was a really bad idea, and the self-healing capability of zfs means that you want a level of redundancy within zfs. So you are inevitably going to lose some extra capacity. Which is better - zfs raidz on hardware mirrors, or zfs mirror on hardware raid-5? I wouldn't rule out raidz (or even raidz2) across multiple arrays that are HW-raid5 internally. My real concern there is the small random read performance issue. -- -Peter Tribble L.I.S., University of Hertfordshire - http://www.herts.ac.uk/ http://www.petertribble.co.uk/ - http://ptribble.blogspot.com/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
