On Wed, 6 Dec 2006, Jim Davis wrote:
We have two aging Netapp filers and can't afford to buy new Netapp gear,
so we've been looking with a lot of interest at building NFS fileservers
running ZFS as a possible future approach. Two issues have come up in the
discussion
- Adding new disks to a RAID-Z pool (Netapps handle adding new disks very
nicely). Mirroring is an alternative, but when you're on a tight budget
losing N/2 disk capacity is painful.
You can add more disks to a pool that is in raid-z you just can't
add disks to the existing raid-z vdev.
The following config was done in two steps:
$ zpool status
pool: cube
state: ONLINE
scrub: scrub completed with 0 errors on Mon Dec 4 03:52:18 2006
config:
NAME STATE READ WRITE CKSUM
cube ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c5t0d0 ONLINE 0 0 0
c5t1d0 ONLINE 0 0 0
c5t2d0 ONLINE 0 0 0
c5t3d0 ONLINE 0 0 0
c5t4d0 ONLINE 0 0 0
c5t5d0 ONLINE 0 0 0
raidz1 ONLINE 0 0 0
c5t8d0 ONLINE 0 0 0
c5t9d0 ONLINE 0 0 0
c5t10d0 ONLINE 0 0 0
c5t11d0 ONLINE 0 0 0
c5t12d0 ONLINE 0 0 0
c5t13d0 ONLINE 0 0 0
The targets t0 through t5 included were added initially, many days
later the targets t8 through t13 were added.
The fact that these are all the same controller isn't relevant.
This is actually what you want with raid-z anyway, in may case above
it wouldn't be good for performance to have 12 disks in the top level
raid-z.
- The default scheme of one filesystem per user runs into problems with
linux NFS clients; on one linux system, with 1300 logins, we already have
to do symlinks with amd because linux systems can't mount more than about
255 filesystems at once. We can of course just have one filesystem
exported, and make /home/student a subdirectory of that, but then we run
into problems with quotas -- and on an undergraduate fileserver, quotas
aren't optional!
So how can OpenSolaris help you with a Linux kernel restriction
on the number of mounts ?
Hey I know, get rid of the Linux boxes and replace them with OpenSolaris
based ones ;-)
Seriously, what are you expecting OpenSolaris and ZFS/NFS in particular
to be able to do about a restriction in Linux ?
--
Darren J Moffat
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