Matthias Appel wrote:
Additionally, with a two disk RAIDZ1 you are doing parity calculations
for
no good reason. I would recommend a mirror.
Will there ever be the possibility to extend a RAIDZ mirror with another
disk?
Linux can do this since kernel 2.6.17 (at least).
I know this is not an really an enterprise feature but enterprise storage
arrays are able to expand a RAID5/6 (even online).
IMHO to expand bulk storage (RAID5/6/Z/Z2) with another spindle would
convince some small enterprises to switch to ZFS.
What do other ZFS guys think of this possibility?
Expanding a RAIDZ (i.e. adding another disk for data, not parity) is a
constantly-asked-for feature.
It's decidedly non-trivial (frankly, I've been staring at the code for a
year now, trying to figure out how, and I'm just not up to the task).
The biggest issue is interrupted expansion - i.e. I've got code to do it
(expansion), but it breaks all over the place when I interrupt the
expansion - horrible pool corruption all the time. And I think that's
the big problem - how to do the expansion in stages, while keeping the
pool active. At this point, the only way I can get it to work is to
offline (ie export) the whole pool, and then pray that nothing
interrupts the expansion process.
That all said, I'm not a /real/ developer, so maybe someone else has
some free time to try.
--
Erik Trimble
Java System Support
Mailstop: usca22-123
Phone: x17195
Santa Clara, CA
Timezone: US/Pacific (GMT-0800)
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
