Re: [zfs-discuss] Performance advantages of spool with 2x raidz2 vdevs vs. Single vdev
Hi guys, I am about to reshape my data spool and am wondering what performance diff. I can expect from the new config. Vs. The old. The old config. Is a pool of a single vdev of 8 disks raidz2. The new pool config is 2vdev's of 7 disk raidz2 in a single pool. I understand it should be better with higher io throughputand better read/write rates...but interested to hear the science behind it. ... FYI, it's just a home serverbut I like it. Some answers (and questions) are here: http://www.opensolaris.org/jive/thread.jspa?threadID=102368tstart=0 *** We need this explained in the ZFS FAQ by a Panel of Experts *** Q: I (we) have a Home Computer and desire to use ZFS with a few large, cheap, (consumer-grade) Drives. What can I expect from 3 Drives, would I be better off with 4 or 5. Please note: I doubt I can afford as many as 10 Drives nor could I stuff them into my Box so please suggest options that use less than that many (most prefefably less than 7). A: ? Thanks, Rob -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
[zfs-discuss] Performance advantages of spool with 2x raidz2 vdevs vs. Single vdev
Hi guys, I am about to reshape my data spool and am wondering what performance diff. I can expect from the new config. Vs. The old. The old config. Is a pool of a single vdev of 8 disks raidz2. The new pool config is 2vdev's of 7 disk raidz2 in a single pool. I understand it should be better with higher io throughputand better read/write rates...but interested to hear the science behind it. I have googles and read the ifs best practice guide and evil tuning, but neither cover my question. Appreciate any advice. FYI, it's just a home serverbut I like it. -- This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Performance advantages of spool with 2x raidz2 vdevs vs. Single vdev
On Mon, 2010-07-19 at 01:28 -0700, tomwaters wrote: Hi guys, I am about to reshape my data spool and am wondering what performance diff. I can expect from the new config. Vs. The old. The old config. Is a pool of a single vdev of 8 disks raidz2. The new pool config is 2vdev's of 7 disk raidz2 in a single pool. I understand it should be better with higher io throughputand better read/write rates...but interested to hear the science behind it. I have googles and read the ifs best practice guide and evil tuning, but neither cover my question. Appreciate any advice. FYI, it's just a home serverbut I like it. Very simple. 2vdevs gives 2 active spindles, so you get about twice the performance of a single disk. raidz2 generally gives the performance of a single disk. For high performance, if you can sacrifice the storage, I recommend a vdev made up of two-drive mirrors. This gives pretty good resilience, and good performance. (Its not as safe as say raidz2, though, because with raidz2 you can lose two drives per vdev, where as with mirrors, you have many more vdevs and can only lose one drive.) With those same 14 drives, you can get 7x the performance instead of 2x the performance by using mirrors instead of raidz2. -- Garrett ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] Performance advantages of spool with 2x raidz2 vdevs vs. Single vdev
On Mon, 19 Jul 2010, Garrett D'Amore wrote: With those same 14 drives, you can get 7x the performance instead of 2x the performance by using mirrors instead of raidz2. This is of course constrained by the limits of the I/O channel. Sometimes the limits of PCI-E or interface cards become the dominant factor. Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, 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
