Replace drives with bigger, all good.

[Aaron Arnold]

I have bought two new drives and am planning to replace two older drives, but was there any way to decided what the drives I should replace.  All drives are heathy. Some have UDMA errors but that was a bad sata cable :(.  Should I just choose the oldest drive, or is there a better metric to go by. 

[Frank1940]

All hard  drives will fail.  That is about the only thing that can be said that is absolutely true.  If there isn't some indicator that a drive has problems, then there is no way to predict which one will fail next. (Especially, in a very small population...)

 

What I would do to pick one to change.  (my personal first choice would be the slowest one.  If they are all about equal from that standpoint, I would probably go with the oldest-- particularly if they have more than 40,000 hours on them.)

 

Set the removed drives on the shelf in storage in case you need to replace a failed drive (assuming there are other drives that are equal in size) in the array.  That way, you have 'replaced' the next drive to fail with a new, larger drive.  😏