On Wed, 26 Nov 2008, Paul Sobey wrote: > > We're more worried about the idea of a single 'zfs filesystem' becoming > corrupt somehow. From what you say below, the pool is the boundry where that > might happen, not the individual filesystem. Therefore it seems no less > dangerous creating a single 5TB pool vs. 10 500GB ones, from a > risk-of-corruption point of view - is that correct?
Other than hardware failure, the biggest fear is some sort of a zfs implementation bug. If there is a zfs implementation bug it could perhaps be more risky to have five pools rather than one. > Given that we have a load of available disks (can't remember exact number for > an X4540 - is it better to chop a storage pool into a few raidz devs then, > rather than all into one? Are there any metrics I can use to guide me in this > as far as performance tuning goes? An important thing to keep in mind is that each vdev offers a "write IOP". If you put ten disks in a raidz2 vdev, then those ten disks are providing one write IOP and a one read IOP. If you use those 10 disks to create five mirror vdevs, then you obtain five write IOPs and ten read IOPs, but almost half the usable disk space. This a a sort of simplistic way to look at the performance issue, but it is still useful. One factor I forgot to mention, is that there is value to having multiple pools if the performance characteristics of the pools needs to be radically different. For example, one pool could be optimized for storage capacity while the other is optimized for IOPS. Bob ====================================== Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
