Hello Jason,

Wednesday, January 10, 2007, 10:54:29 PM, you wrote:

JJWW> Hi Kyle,

JJWW> I think there was a lot of talk about this behavior on the RAIDZ2 vs.
JJWW> RAID-10 thread. My understanding from that discussion was that every
JJWW> write stripes the block across all disks on a RAIDZ/Z2 group, thereby
JJWW> making writing the group no faster than writing to a single disk.
JJWW> However reads are much faster, as all the disk are activated in the
JJWW> read process.

The opposite actually. Because of COW, writing (modifying as well)
will give you up-to N-1 disks performance for raid-z1 and N-2 disks performance 
for
raid-z2. Howeer reading can be slow in case of many small random reads
as to read each fs block you've got to wait for all data disks in a
group.


JJWW> The default config on the X4500 we received recently was RAIDZ-groups
JJWW> of 6 disks (across the 6 controllers) striped together into one large
JJWW> zpool.

However the problem with that config is lack of hot-spare.
Of course it depends what you want (and there was no hot spare support
in U2 which is os installed in factory so far).


-- 
Best regards,
 Robert                            mailto:[EMAIL PROTECTED]
                                       http://milek.blogspot.com

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