Hi, 

I have a PS6510 which was showing a couple of drives amber with "history of failures". Mid last week, I replaced one of the drives and found out the next day that replaced drive was happy but another drive now appeared to have failed. On Friday, I replaced the failed drive and left the system alone. I checked the system again today and found out that replaced drive was fine again but another drive has failed. 

I now have a failed drive and still one drive with "history of failures" message. I am just wondering if I am doing anything stupid or if this is normal. 

I have one more spare drive that can replace the failed drive but I fear that may trigger another drive failure. I can get more replacement but just like to understand what is going on. 

Any help on this will be greatly received. Thanks!