On Sat, February 5, 2011 03:54, Gaikokujin Kyofusho wrote: > From what I understand using ZFS one could setup something like RAID 6 > (RAID-Z2?) but with the ability to use drives of varying > sizes/speeds/brands and able to add additional drives later. Am I about > right? If so I will continue studying up on this if not then I guess I > need to continue exploring different options. Thanks!!
IMHO, your best bet for this kind of configuration is to use mirror pairs, not RAIDZ*. Because... Things you can't do with RAIDZ*: You cannot remove a vdev from a pool. You cannot make a RAIDZ* vdev smaller (fewer disks). You cannot make a RAIDZ* vdev larger (more disks). To increase the storage capacity of a RAIDZ* vdev you need to replace all the drives, one at a time, waiting for resilver between replacements (resilver times can be VERY long with big modern drives). And during each resilver, your redundancy will be reduced by 1 -- meaning a RAIDZ array would have NO redundancy during the resilver. (And activity in the pool is high during the resilver -- meaning the chances of any marginal drive crapping out are higher than normal during the resilver.) With mirrors, you can add new space by adding simply two drives (add a new mirror vdev). You can upgrade an existing mirror by replacing only two drives. You can upgrade an existing mirror without reducing redundancy below your starting point ever -- you attach a new drive, wait for the resilver to complete (at this point you have a three-way mirror), then detach one of the original drives; repeat for another new drive and the other original drive. Obviously, using mirrors requires you to buy more drives for any given amount of usable space. I must admit that my 8-bay hot-swap ZFS server cost me a LOT more than a Drobo (but then I bought in 2006, too). -- David Dyer-Bennet, d...@dd-b.net; http://dd-b.net/ Snapshots: http://dd-b.net/dd-b/SnapshotAlbum/data/ Photos: http://dd-b.net/photography/gallery/ Dragaera: http://dragaera.info _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
