On Thu, Aug 03, 2006 at 10:24:12AM -0700, Marion Hakanson wrote: > > zpool create mirror c0t2d0 c0t3d0 mirror c0t0d0s5 c0t1d0s5 > > Is this allowed? Is it stupid? Will performance be so bad/bizarre that > it should be avoided at all costs? Anybody tried it? >
Yes, it's allowed, but it's definitely not an ideal solution. Unless you manually tweak the write cache (as mentioned elsewhere, this could be bad for other slices), you'll end up with asymmetric performance on these two vdevs. The current ZFS allocation and I/O policies don't take latency into account (they're based solely on capacity), and so a slower vdev will slow down the entire pool. Future work will make ZFS behave better in the face of asymmetric performance, but in general this will still be a non-ideal configuration. You'll be fighting with other filesystems for control of the underlying disk, you won't be able to use hot spares effectively, and future FMA work (such as reading SMART data and predictive analysis) may not work well (if at all). - Eric -- Eric Schrock, Solaris Kernel Development http://blogs.sun.com/eschrock _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
