On Wed, 11 Nov 2009, Rob Logan wrote:
from a two disk (10krpm) mirror layout to a three disk raidz-1.
wrights will be unnoticeably slower for raidz1 because of parity calculation
and latency of a third spindle. but reads will be 1/2 the speed
of the mirror because it can split the reads between two disks.
But with raidz1 a data block will be split (striped) across two disks.
Doesn't that also speed up the reads (assuming that at least the zfs
record size is requested)?
We were told that scheduled reads from mirrors is done using an
algorithm which do not assure that sequential reads will be read from
different disks in a mirror pair. Sometimes sequential reads may be
from the same side of the mirror.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
