I have 4 disks in a raid10 array into a dell server. 2 drives are failed right now. The failed drives are not in the same group (1+2 and 3+4), drives failed are 2 and 3. The server is still running, but the array is degraded. I'm waiting the new drives to arrive.
What is the best way to replace drives? Can I replace both disks at the same time or it's better to rebuild the first group first then replace the other?
Make sure you have an up-to-date backup. If, for whatever reason, you don’t - start evacuating your data immediately! Don’t do it in parallel with the RAID rebuild as it puts more pressure on disks and instead of the streamline process you’ll get tons of random I/O killing performance. One you really need to get data somewhere ASAP.
Replace faulty disks one-by-one. Doing a parallel rebuild in this case is going to be slower actually, and it’s not what you want.
Hope this helped.
P.S. You’ve been exceptionally lucky already as disks didn’t fail within same RAID1 group. Don’t stretch your luck thin!
Not sure about the PERC but I'd replace one drive at a time. Most likely the controller schedules two rebuilds and only runs one of them at a time anyway.
Of course, you should have a reliable and tested backup at all times.
