On Tue, 20 Nov 2007, Tim Cook wrote: > So I have 8 drives total. > > 5x500GB seagate 7200.10 > 3x300GB seagate 7200.10 > > I'm trying to decide, would I be better off just creating two separate pools? > > pool1 = 5x500gb raidz > pool2= 3x300gb raidz
... reformatted ... > or would I be better off creating one large pool, with two raid > sets? I'm trying to figure out if it would be faster this way since > it should be striping across the two pools (from what I understand). > On the other hand, the pool of 3 disks is obviously going to be much > slower than the pool of 5. > > In a perfect world I'd just benchmark both ways, but due to some > constraints, that may not be possible. Any insight? > Hi Tim, Let me give you a 3rd option for your consideration. In general, there is no "one-pool-fits-all-workloads" solution. On a 10 disk system here, we ended up with a: 5 disk raidz1 pool 2 disk mirror pool 3 disk mirror pool Each have their strengths/weaknesses. The raidz set is ideal for large file sequential access type workloads - but the IOPS are limited to the IOPS of a single drive. The 3-way mirror is ideal for a workload with a high read to write ratio - which describes many real-world type workloads (e.g. software development) - since ZFS will load balance read ops amoung all members of the mirror set. So read IOPS is 3x the IOPS rating of a single disk. I would suggest/recommend you configure a 5 disk raidz1 pool (with the 500Gb disks) and a 2nd pool using a 3-way mirror. You can then match pool/filesystems to the best fit with your different workloads. Remember the incredibly useful blogs at: http://blogs.sun.com/relling/ (Thank you Richard) to determine the relative reliability/failure rates of different ZFS configs. PS: If we had to do it over, I'd probably go with a 6-disk raidz2, in place of the 5-disk raidz1 - due to the much higher relibility of that config. Regards, Al Hopper Logical Approach Inc, Plano, TX. [EMAIL PROTECTED] Voice: 972.379.2133 Fax: 972.379.2134 Timezone: US CDT OpenSolaris Governing Board (OGB) Member - Apr 2005 to Mar 2007 http://www.opensolaris.org/os/community/ogb/ogb_2005-2007/ Graduate from "sugar-coating school"? Sorry - I never attended! :) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
