Thanks for the tip. I was unable to shut down the machine yet, as the virtualized Exchange is mission critical.
First I'll try to find out a way to backup the Exchange database (without corrupting it, the file is more fragile than a wine glass) and then I'll setup write-back mode. The setting shouldn't discard the array hopefully :s
The thing is I'm not sure if it is possible to change the PERC 200H controller into some that supports battery backed up caching without disbanding the array and being offline for a day, or if it is even possible with DELL R310 (to get some better controller model with battery) - it's a 1U unit
