Which disk is active in "Failed redundancy" situation on mirrored volume?

[Gera2]

Hello

A kind of difficult situation in some details: Windows 2003 R2 x64 + two
MSA1000 with several RAID5 LUNs each.
Corresponding LUNs from both MSA are mirrored on Windows level.
Now MSA01 has hardware problems and fails from time to time, after what
Windows loses all those LUNs for a second and after reboot
Disk Management shows as "Online with Failed Rredundancy".
The only local support HP suggestion is to recreate that Array on MSA01 with all three
LUNs.

Before doing that I have a very serious question - how to know which side of
mirror Windows are now writing the data to?
If it is going to the failing side (MSA01) - I will have to do
backup/restore (almost impossible due to possible downtime window)
If the system is using good part (MSA02) - then I will simply delete LUN's
from MSA01, remove from Disk Management, recreate array and "Add mirror"
(breaking the mirror isn't possible because the synchr. isn't complete).
Or, any other advice?

So, what is Windows behavior in such situation?

P.S. Sinchronising the volume probably will not be the option, because it
progresses very slow, and seems to fail at some point.
Or the storage fails before it finishes, and the process starts over.


Thanks,
Gera,
Baltic Data Center