which is it the drives or the controller cards ??
whats the working environment ??
Data center ?
are they on UPS power ?
temp control ?
brand and models of drives ?
I have setup arrays that run for 2-3 years with parhaps 1 or 2 drive losses but never 2 at the same time....
For the record:
It is 4 identical Seagate 73GB SCSI HDD(ST373207LW) forming RAID 10 on a Adaptec 2130S controller.
A system check reveiled the Drive1 failed, and the Drive0 is in fact ok.
The server was located in a server rack inside our company's office, with 24hrs air-conditioning and UPS attached.