On Wed, 7 May 2008, Paul B. Henson wrote: > > I was thinking about allocating 2 drives for the OS (SVM mirroring, pending > ZFS boot support), two hot spares, and allocating the other 44 drives as > mirror pairs into a single pool. While this will result in lower available > space than raidz, my understanding is that it should provide much better > performance. Is there anything potentially problematic about this > configuration? Low-level disk performance analysis is not really my field,
It sounds quite solid. The load should be quite nicely distributed across the mirrors. > It seems like kind of a waste to allocate 1TB to the operating system, > would there be any issue in taking a slice of those boot disks and creating > a zfs mirror with them to add to the pool? You don't want to go there. Keep in mind that there is currently no way to reclaim a device after it has been added to the pool other than substituting another device for it. Also, the write performance to these slices would be less than normal. If I was you, I would keep more disks spare in the beginning and see how the system is working. If everything is working great, then add more disks to the pool. Once disks are added to the pool, they are comitted. An advantage of load-shared mirrors is that more pairs can be added at any time. You need enough disks in the system to satisfy current disk space and I/O rate requirements, but it is not necessary to start off with all the disks added to the pool. Disks added earlier will be initially more loaded up than disks added later. 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
