Hello Phillip, Thursday, May 17, 2007, 6:30:38 PM, you wrote:
PF> [b]Given[/b]: A Solaris 10 u3 server with an externally attached PF> disk array with RAID controller(s) PF> [b]Question[/b]: Is it better to create a zpool from a PF> [u]single[/u] external LUN on an external disk array, or is it PF> better to use no RAID on the disk array and just present PF> individual disks to the server and let ZFS take care of the RAID? There's no simple answer :))) Depends on things like what kind of RAID you want to use and what is your IO characteristic. For example if you want to use RAID-5 and you are issuing lot of small asynchronous writes then RAID-Z should give you more performance than HW RAID-5. But if you want RAID-5 and lot of concurent random small reads then HW RAID-5 will be generally better than RAID-Z. If your workload is mixed then... well. However putting ZFS on top of HW RAID-5 in many cases mitigates write problem due to "converting" most random writes into sequential aggregated writes. Then other thing - do you use SATA disks? How much data loss or corruption is an issue for you? Doing software RAID in ZFS can detect AND correct such problems. HW RAID also can but to much less extent. On the other hand current hot spare support in ZFS is lacking and generally when it comes to data availability HW RAID offers better hot spare support. It's being worked on. But you may want to buy JBOD and not spend money on controllers which can save you some money. Then once your environment grows and you end up with many arrays from different vendors going with SW solutions simplifies and unifies storage management. Se my blog for some performance comparisons for HW RAID vs. SW RAID in ZFS. PF> [b]Example[/b]: I have a Solaris 10 server with an attached 3320 PF> disk array and want to use ZFS instead of UFS. Should I create a PF> single RAID protected LUN on the 3320 and build a single disk ZFS PF> pool on it, or should I setup each disk in the 3320 as an "NRAID" PF> (aka individual disk) to be used by the server in a multi-disk zfs pool? see above Personally I would go with ZFS entirely in most cases. -- Best regards, Robert Milkowski mailto:[EMAIL PROTECTED] http://milek.blogspot.com _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
