Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread grant beattie
On Thu, Jul 13, 2006 at 11:42:21AM -0700, Richard Elling wrote: > >Yes, and while it's not an immediate showstopper for me, I'll want to > >know that expansion is coming imminently before I adopt RAID-Z. > > [in brainstorming mode, sans coffee so far this morning] > > Better yet, buy two disks,

[zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Tatjana S Heuser
> Of course when it's time to upgrade you can always > just call sun and get a Thumper on a "Try before you > Buy" - and use it as a temporary storage space for > your files while you re-do your raidz/raidz2 virtual > device from scratch with an additional disk. zfs > send/zfs recieve here I come..

Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Erik Trimble
On Thu, 2006-07-13 at 11:42 -0700, Richard Elling wrote: > [in brainstorming mode, sans coffee so far this morning] > > Better yet, buy two disks, say 500 GByte. Need more space, replace > them with 750 GByte, because by then the price of the 750 GByte disks > will be as low as the 250 GByte disk

Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Richard Elling
David Abrahams wrote: David Dyer-Bennet <[EMAIL PROTECTED]> writes: Adam Leventhal <[EMAIL PROTECTED]> writes: I'm not sure I even agree with the notion that this is a real problem (and if it is, I don't think is easily solved). Stripe widths are a function of the expected failure rate and

Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Rob Logan
comfortable with having 2 parity drives for 12 disks, the thread starting config of 4 disks per controller(?): zpool create tank raidz2 c1t1d0 c1t2d0 c1t3d0 c1t4d0c2t1d0 c2t2d0 then later zpool add tank raidz2 c2t3d0 c2t4d0 c3t1d0 c3t2d0 c3t3d0 c3t4d0 as described, doubles ones IOPs,

[zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Scott Roberts
Of course when it's time to upgrade you can always just call sun and get a Thumper on a "Try before you Buy" - and use it as a temporary storage space for your files while you re-do your raidz/raidz2 virtual device from scratch with an additional disk. zfs send/zfs recieve here I come. Not

[zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread David Abrahams
David Dyer-Bennet <[EMAIL PROTECTED]> writes: > Adam Leventhal <[EMAIL PROTECTED]> writes: > >> I'm not sure I even agree with the notion that this is a real >> problem (and if it is, I don't think is easily solved). Stripe >> widths are a function of the expected failure rate and fault domains >>

[zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread David Abrahams
Jeff Bonwick <[EMAIL PROTECTED]> writes: > The main issues are administrative. ZFS is all about ease of use > (when it's not busy being all about data integrity), so getting the > interface to be simple and intuitive is important -- and not as > simple as it sounds. If your free disk space might

Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Luke Scharf
David Dyer-Bennet wrote: It's easy to corrupt the volume, though -- just copy random data over *two* disks of a RAIDZ volume. Okay, you have to either do the whole volume, or get a little lucky to hit both copies of some piece of information before you get corruption. Or pull two disks out of t

Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread David Dyer-Bennet
Luke Scharf <[EMAIL PROTECTED]> writes: > As for the claims, I don't buy that it's impossible to corrupt a ZFS > volume. I've replicated the demo where the guy dd's /dev/urandom > over part of the disk, and I believe that works -- but there are a > lot of other ways to corrupt a filesystem in the

Re: [zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Luke Scharf
David Abrahams wrote: I've seen people wondering if ZFS was a scam because the claims just seemed too good to be true. Given that ZFS *is* really great, I don't think it would hurt to prominently advertise limitations like this one it would probably benefit credibility considerably, and it's a r

[zfs-discuss] Re: Expanding raidz2

2006-07-13 Thread Scott Roberts
If it was possible to implement raidz/raidz2 expansion it would be a big feature in favor of ZFS. Most hardware RAID controllers have the ability to expand a raid pool - some have to take the raid array offline, but the ones I work with generally do it online, although you are forced to suffer t

[zfs-discuss] Re: Expanding raidz2

2006-07-12 Thread David Abrahams
David Dyer-Bennet <[EMAIL PROTECTED]> writes: > It does, as you say, take up another whole parity disk (or two in your > raidz2 case). And requires add-ons to be in units bigger than just > one drive. I've seen people wondering if ZFS was a scam because the claims just seemed too good to be tru