On Fri, 29 Aug 2008, Kenny wrote: > > 1) I didn't do raid2 because I didn't want to lose the space. Is > this a bas idea??
Raidz2 is the most reliable vdev configuration other than triple-mirror. The pool is only as strong as its weakest vdev. In private email I suggested using all 12 drives in two raidz2 vdevs. Other than due to natural disaster or other physical mishap, the probability that enough drives will independently fail to cause data loss in raidz2 is similar to winning the state lottery jackpot. Your Sun service contract should be able to get you a replacement drive by the next day. A lot depends on if there are system administrators paying attention to the system who can take care of issues right away. If system administration is spotty or there is no one on site, then the ZFS spare is much more useful. Using more vdevs provides more multi-user performance, which is important to your logging requirements. If you do use the two raidz2 vdevs, then if you pay attention to how MPxIO works, you can balance the load across your two fiber channel links for best performance. Each raidz2 vdev can be served (by default) by a differente FC link. If you do enable compression, then that will surely make up for the additional space overhead of two raidz2 vdevs. > 3) I have intentionally skipped the hardware hotspare and RAID > methods. Is this a good idea?? What would be the best method to > intergrate both hardware and software With the hardware JBOD approach, having the 2540 manage the hot spare would not make sense. > 4) A fellow admin here voiced concern with having ZFS handle the > spare and raid functions. Specifically that the overhead processing > would affect performance. Does anyone have experiance with server > performance in this manner? Having ZFS manage the spare costs nothing. There will be additional overhead when building the replacement drive, but this overhead would be seen if the drive array handled it too. Regardless, the drive array does not have the required information to build the drive. ZFS does have that information so ZFS should be in charge of the spare drive. > 5) If I wanted to add an additional disk tray in the near future (12 > more 1TB disk), what would be the recommended method? I was > thinking of simply createing additional vdevs and adding them to the > zpool. That is a sensible approach. If you know you will be running out of space, then it is best to install the additional hardware sooner than later since otherwise most of the data will be on the vdevs which were active first. ZFS does not currently provide a way to re-write a pool so that it is better balanced across vdevs. 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
