On Thu, January 14, 2010 09:44, Mr. T Doodle wrote: > I have played with ZFS but not deployed any production systems using ZFS > and > would like some opinions....
Opinions I've got :-). Nor am I at all unusual in that regard, on this list :-) :-). > I have a T-series box with 4 internal drives and would like to deploy ZFS > with availability and performance in mind.... ;) > > What would some recommended configurations be? > Example: use internal RAID controller to mirror boot drives, and ZFS the > other 2? We haven't discussed configurations this small much lately, but I'm sure people will have ideas. And there isn't enough there to really give you many options, unfortunately. Lots of people think that ZFS does better than hardware controllers (at keeping the data valid). Modern OpenSolaris will install a ZFS pool and put the system filesystems in it (and use snapshots and such to manage upgrades, too). And you can then manually attach a second disk for redundancy, for that "availability" goal. However, you can't use a RAIDZ vdev, only a single device or a mirror. So you can't put all the disks into one ZFS pool and boot off it and serve the rest of the space out for other uses. (Boot code has to support the parts of ZFS that you can configure it to boot from, so it's a quite restricted subset). You could eat two disks for redundant boot pool, and then have the other two left to share out (presumably as a mirror vdev in a zpool), but that wastes a high percentage of your disk (1 drive usable out of 4 physical). You could have a non-redundant boot disk and then make a three-disk RAIDZ pool to share out, but of course that takes the server down if the one boot disk fails. > Can I create one pool with the 3 or 4 drives, install Solaris, and use > this pool for other apps? Nope, that's the thing you can't do. > Also, what happens if a drive fails? Depends on the kinds of vdevs; if there's redundancy (mirror or RAIDZ[123]), you can replace the bad drive, resilver, and keep running. If these aren't hot-swap drives, you'll have to shut down to make the physical switch. If you want availability, you should choose vdev types with redundancy of course. > Thanks for any tips and gotchas. One interesting possibility, which I haven't worked with but which sounds good, for this kind of low-end server, is to set the system up to boot from a USB key rather than the disks. This is slower, but system disk access isn't very frequent. And instead of real redundancy on the boot drive (with auto-failover), just keep another copy of the key, and plug that one in instead if the first one fails. Then you could put all four disks in a RAIDZ pool and share them out for use, with redundancy &c. I'm used to the x86 side, not sure if the boot-from-USB thing is supported on a T-series box, either. -- 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
