this sounds right. Theres also the problem of adding non-redundant types to redundant types...but yah, it kind of defeats the purpose, The thing people seem to miss, is ZFS comes with a price, that price is you need to plan your pool AND expansion plan ahead of time. If you want to grow pools with small numbers of disks, use mirrored vdevs.
On Mon, Aug 10, 2009 at 6:30 PM, Brian Hechinger <wo...@4amlunch.net> wrote: > On Mon, Aug 10, 2009 at 05:16:27PM -0500, Bob Friesenhahn wrote: > > On Mon, 10 Aug 2009, Thomas Burgess wrote: > > > > >i think you can add different types of vdevs but doesn't it make you use > > >-f? > > >i thought it was "not a good idea" > > > > I have no idea. I am not brave enough to try it with my own pool and > > am too lazy to test with files. > > > > There are lots of things you can do wrong. For example, you could > > have two vdevs with the same organization, but with radically > > different disk performance. > > If I'm not mistaken, the "only downside" to mixing and matching disks > and/or > vdev types is that the entire zpool's performance is limited by the lowest > common denominator. Add a fast mirror to your slow raidz pool and you'll > only increase the space. Add a slow raidz vdev to your fast mirror pool > and > you'll add space and reduce the performance. > > I'm not 100% sure on that, but I seem to remember that being the only > potential > problem. > > -brian > -- > "Coding in C is like sending a 3 year old to do groceries. You gotta > tell them exactly what you want or you'll end up with a cupboard full of > pop tarts and pancake mix." -- IRC User (http://www.bash.org/?841435) > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss >
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