Yes, that is true. If you have 4 2 TB drives, you would only get 4 TBs
of usable disk space in a mirrored config.
The problem I see with your potential RAIDZ config, if I understand
it correctly, is that you can't add more disks to an existing RAIDZ
config. You would need to create a 3 disk RAIDZ1 config with 1 spare
or a 4 disk RAIDZ1 config. You can't attach more disks to an existing
RAIDZ config.
I understand that using all potential disk capacity is a priority, but
I've been listening to this list for a long time and have come to
appreciate the flexibility and reliability of mirrored configs.
cs
On 07/14/10 14:38, Daniel Taylor wrote:
Cindy,
Thanks for getting back to me so quickly,
I had though about that idea but (forgive me if I'm wrong) won't that
leave me with 4TB of space free from my (eventual) 8TB's worth of drives?
So 2 of the 2TB drives will be used just for mirroring. Where as with
RaidZ I'd only lose one drive and have 3 usable (so 6TB, which is what I
was going for)
I can only fit 4 drives into the server chassis and I was hoping to get
6TB out of it.
Thanks,
- Daniel
On 14 Jul 2010, at 21:28, Cindy Swearingen wrote:
Hi Daniel,
No conversion from a mirrored to RAIDZ configuration is available yet.
Mirrored pools are more flexible and generally provide good performance.
You can easily create a mirrored pool of two disks and then add two
more disks later. You can also replace each disk with larger disks
if needed. See the example below.
If you consider that disks are relatively inexpensive, then a mirrored
configuration is a very good option.
Thanks,
Cindy
# zpool create mpool mirror c2t6d0 c2t7d0
# zpool list mpool
NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT
mpool 136G 78.5K 136G 0% 1.00x ONLINE -
# zpool status mpool
pool: mpool
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
mpool ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c2t6d0 ONLINE 0 0 0
c2t7d0 ONLINE 0 0 0
errors: No known data errors
# zpool add mpool mirror c2t8d0 c2t10d0
# zpool list mpool
NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT
mpool 272G 138K 272G 0% 1.00x ONLINE -
# zpool status mpool
pool: mpool
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
mpool ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c2t6d0 ONLINE 0 0 0
c2t7d0 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
c2t8d0 ONLINE 0 0 0
c2t10d0 ONLINE 0 0 0
errors: No known data errors
On 07/14/10 13:58, Daniel Taylor wrote:
Hello,
I'm about the build a opensolaris NAS system, currently we have two
drives and are planning on adding two more at a later date (2TB
enterprise level HDD are a bit expensive!).
Whats the best configuration for setting up these drives bearing in
mind I want to expand in the future?
I was thinking of mirroring the drives and then converting to raidz
some how?
It will only be a max of 4 drives, the second two of which will be
bought later.
Any ideas?
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
