On Thu, 18 Feb 2010, Edward Ned Harvey wrote:
Actually, that's easy. Although the "zpool create" happens instantly, all
the hardware raid configurations required an initial resilver. And they
were exactly what you expect. Write 1 Gbit/s until you reach the size of
the drive. I watched the progress while I did other things, and it was
incredibly consistent.
This sounds like an initial 'silver' rather than a 'resilver'. In a
'resilver' process it is necessary to read other disks in the vdev in
order to reconstruct the disk content. As a result, we now have
additional seeks and reads going on, which seems considerably
different than pure writes.
What I am interested in is the answer to these sort of questions:
o Does a mirror device resilver faster than raidz?
o Does a mirror device in a triple mirror resilver faster than a
two-device mirror?
o Does a raidz2 with 9 disks resilver faster or slower than one with
6 disks?
The answer to these questions could vary depending on how well the
pool has been "aged" and if it has been used for a while close to 100%
full.
Before someone pipes up and says that measuring this is useless since
results like this are posted all over the internet, I challenge that
someone to find this data already published somewhere.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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