Ok! now im with us!
.. hmm. that makes more sense actually..
thank you for the time to explain that to me :)
- Hide quoted text -
On 7/10/07, Adam Leventhal <ahl@eng.sun.com> wrote:
> That's right.
>
> Adam
>
> On Tue, Jul 10, 2007 at 01:42:23PM -0400, Echo B wrote:
> > What youre saying is that id have several raidz's to a zpool, and then
> > when i needed more space, id make a new raidz, and add that to the
> > zpool as well?
> >
> > On 7/10/07, Adam Leventhal <ahl@eng.sun.com> wrote:
> > >Hi Jason,
> > >
> > >Unfortunately, RAID doesn't work that way. It needs to distribute your data
> > >over all the drives. If you were to have five drives and fill to three-
> > >quarters capacity, adding an additional drive wouldn't give you the
> > >reliability associated with RAID without redistributing the extant data.
> > >I suppose "widening" a stripe would be possible, but it would be very very
> > >difficult.
> > >
> > >You really have to commit to a unit of expansion and the number of failures
> > >you want to be able to survive within a given unit. For example, you could
> > >add drives in pairs and survive a single failure within each pair. My guess
> > >is that it might make sense for you to use a relatively small RAID stripe
> > >width (2+1 or 3+1) and then commit to adding drives 3 or 4 at a time.
> > >
> > >Adam
> > >
> > >On Tue, Jul 10, 2007 at 01:25:04PM -0400, Echo B wrote:
> > >> I am a bit of a RAID noob in general. But the ultimate goal is to have
> > >> one file system that can keep getting bigger and bigger and bigger....
> > >>
> > >> My plan was to do something that isn't possible yet. Which was to add
> > >> a drive or two and simply grow the raid-z by that capacity.
> > >>
> > >>
> > >> On 7/10/07, Adam Leventhal <ahl@eng.sun.com> wrote:
> > >> >So your plan is to expand from a 4 + 1, say, to a 6 + 1 stripe? I don't
> > >> >think that would be possible. I thought you might want to go from 4 + 1
> > >to
> > >> >4 + 2 which is possible, but difficult.
> > >> >
> > >> >Adam
> > >> >
> > >> >On Tue, Jul 10, 2007 at 09:39:03AM -0400, Echo B wrote:
> > >> >> Adam,
> > >> >> Thanks for the reply!
> > >> >> I do - I am setting up a Raid-Z 2 with 5 1TB disks. This is for my own
> > >> >> small company, not a larger company with a larger budget. I currently
> > >> >> house about 2TB of data. And within the year I expect my space needs
> > >> >> to grow. Given that the hard drive investment just cost me nearly $2k,
> > >> >> I cannot justify another $2k + in a hear when it is time to expand.
> > >> >> Perhaps I am alone in this thought? If Raid-Z is so reliable for the
> > >> >> data, it only makes sense that ppl wouldn't want to migrate off of it.
> > >> >> As such, give them a batter growth path.
> > >> >> I have a HW RAID controller that supports online growth (Areca
> > >> >> ARC-1230) - and may well go with UFS2 because of growfs.
> > >> >>
> > >> >> I LOVE the feature set and capabilities of ZFS however and would much
> > >> >> prefer to use that.
> > >> >>
> > >> >> Sincerely,
> > >> >>
> > >> >> :Jason
> > >> >>
> > >> >> On 7/10/07, Adam Leventhal <ahl@eng.sun.com> wrote:
> > >> >> >As has been mentioned on this forum, this would require a significant
> > >> >> >change
> > >> >> >to the way RAID-Z works. To my knowledge there is no such project at
> > >> >> >present.
> > >> >> >Do you have a use case where this is required?
> > >> >> >
> > >> >> >Adam
> > >> >> >
> > >> >> >On Sat, Jul 07, 2007 at 03:37:19PM -0400, Echo B wrote:
> > >> >> >> Apologies for the blank message (if it came through).
> > >> >> >>
> > >> >> >> I have heard here and there that there might be in development a
> > >plan
> > >> >> >> to make it such that a raid-z can grow its "raid-z'ness" to
> > >> >> >> accommodate a new disk added to it.
> > >> >> >> Example:
> > >> >> >> I have 4Disks in a raid-z[12] configuration. I am uncomfortably
> > >low on
> > >> >> >> space, and would like to add a 5th disk. The idea is to pop in
> > >disk 5
> > >> >> >> and have the raid-z expand its feature set and free space to
> > >> >> >> incorporate the 5th disk.
> > >> >> >>
> > >> >> >> Is there indeed such a thing in the works? Or in consideration?
> > >> >> >> _______________________________________________
> > >> >> >> zfs-code mailing list
> > >> >> >> zfs-code@opensolaris.org
> > >> >> >> http://mail.opensolaris.org/mailman/listinfo/zfs-code
> > >> >> >
> > >> >> >--
> > >> >> >Adam Leventhal, Solaris Kernel Development
> > >> >http://blogs.sun.com/ahl
> > >> >> >
> > >> >
> > >> >--
> > >> >Adam Leventhal, Solaris Kernel Development
> > >http://blogs.sun.com/ahl
> > >> >
> > >
> > >--
> > >Adam Leventhal, Solaris Kernel Development http://blogs.sun.com/ahl
> > >
>
> --
> Adam Leventhal, Solaris Kernel Development http://blogs.sun.com/ahl