Richard Elling wrote:
On Apr 14, 2010, at 8:57 AM, Yariv Graf wrote:
From my experience dealing with > 4TB you stop writing after 80% of zpool
utilization
YMMV. I have routinely completely filled zpools. There have been some
improvements in performance of allocations when free space gets low in
the past 6-9 months, so later releases are more efficient.
-- richard
I would echo Richard here, and add that it also seems to be dependent on
the usage characteristics.
That is, using in a write-mostly (or, write-almost-exclusively) form
seems to result in no problems filling a pool to 100% - so, if you're
going to use the zpool for (say) storing your DVD images (or other
media-server applications), then go ahead, and plan to fill the pool up.
On the other hand, doing lots of write/erase stuff (particularly with a
wide mix of file sizes) does indeed seem to cause performance to drop
off rather quickly once 80% (or thereabouts) capacity is reached. For
instance - I routinely back up my local developers' workstation's disks
to a ZFS box using rsync, rapidly changing the contents of my zpool each
night (as I also expire old backups more than 1 week old). That machine
hits a brick wall on performance at about 82% full (6-disk 250GB
7200RPM SATA in a raidz1).
--
Erik Trimble
Java System Support
Mailstop: usca22-123
Phone: x17195
Santa Clara, CA
Timezone: US/Pacific (GMT-0800)
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