Thanks for the information... In my case, I do not have a root pool, its still UFS.
The configuration is essentially that I have two arrays. The system was initially built with one array. A zfs pool was created from the whole disks on the array. The pool is more or less used for general storage. Along comes a second array, with different number of and size disks. It will be used for more or less the same thing. So the question is whether I should add to the original pool or create a second pool. One thing you mention is rather curious, "all vdevs should be mirrored, or the same nr of columns in the stripe or raidz. This is not a restriction, just a strong recommendation". If I add the second array to the pool, I could probably continue with the same number of columns in the raidz, but the size of the strips would increase. Would this effect performance somehow? --joe Johan Hartzenberg wrote: > > On Wed, Oct 8, 2008 at 9:29 PM, Joseph Mocker > <[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]>> wrote: > > Hello, > > I haven't seen this discussed before. Any pointers would be > appreciated. > > I'm curious, if I have a set of disks in a system, is there any > benefit > or disadvantage to breaking the disks into multiple pools instead of a > single pool? > > Does multiple pools cause any additional overhead for ZFS, for > example? > Can it cause cache contention/starvation issues? > > > Hello Joseph. > > Firstly, a separate pool for the OS is recommended. The pool from > which you boot must be either Mirrored or else a single disk. Booting > from Stripes / RaidZ is not supported. Thus if you want to use a > stripe or RaidZ you pretty much MUST have a dedicated pool for that. > > Secondly, if you use whole disks in your pools, it becomes possible to > physically "remove" a pool (using zpool export), eg to move a pool to > another system. > > Further, it is recommended to use the same level of redundancy in all > vdev's. Eg all vdevs should be mirrored, or the same nr of columns in > the stripe or raidz. This is not a restriction, just a strong > recommendation. > > Never ever add multiple slices (partitions) from a single disk device > to the same pool - this will cause performance to go down to a crawl! > > You can not (yet) "break up" a pool, though you can break off a mirror > copy. And to stay in line with the above recommendations, you may > want more than one pool. For best performance you should use > whole-disks in pools, but sometimes for practical reasons you may want > to spit a single disk up in slices and add those to separate pools. > > Hope that helps! > _hartz > > -- > Any sufficiently advanced technology is indistinguishable from magic. > Arthur C. Clarke > > Afrikaanse Stap Website: http://www.bloukous.co.za > > My blog: http://initialprogramload.blogspot.com > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
