ZFS Warning Since Upgrade to 10.0

[Tim Gustafson]

I recently upgraded a ZFS file server from 9.2 to 10.0 and then
started getting this warning when I run zpool status:

status: One or more devices are configured to use a non-native block
size. Expect reduced performance.
action: Replace affected devices with devices that support the
configured block size, or migrate data to a properly configured pool.

I Googled around a bit, and understand the warning, but I have a
problem: that zpool is 135TB and I don't have 135TB of disks laying
around, nor the controllers necessary to support an additional 135TB
of disks, to migrate this zpool to a properly configured one, nor
could I easily have the server off-line for the requisite time that
would be required to transfer 100+ TB of data from one set of hard
drives to another.

So my questions are:

How much will this sub-optimal configuration affect performance?

Does the upgrade to 10.0 represent a reduction in performance, or was
the reduction in performance always there and just not reported?  This
server is used to store genome data, so performance is pretty
important, but the users were happy with the performance when it was a
9.2 server.

If I convince the users to go through an upgrade process to fix this
issue, how much of a boost in performance can they expect to see?  If
it's a 2% boost, I don't think I can get them to invest in the
upgrade, but it it's a 100% boost, I'm pretty sure I can.

-- 

Tim Gustafson
tjg at ucsc.edu
831-459-5354
Baskin Engineering, Room 313A