VA rebuild priority - low or high?

[Steve Lewis]

After waiting 15 hours for my 1Tb VA7410 (RAID 1/0, hot spare=largest disk) to rebuild following a failed 146gb disk (currently 84% complete) I was wondering what other people set their rebuild priority to.

We have ours set to low priority rebuild and automatic.
I realise that kicking the users off makes a difference too, but our background tasks are time-critical and need to be left running which is affecting rebuild performance.

We are hypothesizing that setting the priority to high and bearing very bad performance for a shorter period of time may be better than setting the rebuild priority to low and suffering poor performance for a longer period. Even though the priority is low, user processes are taking about 12 times longer than usual.

Has anyone tried setting HIGH priority and what sort of difference have they found it made to rebuild times?