ReadyNAS - A RAID that is not a RAID

mdgm wrote:

Disks can and do fail at any time and in various ways. Especially if the disk failure manages to go undetected this can cause issues. Did you get any email alerts about SMART errors to warn you that this disk was having issues? The Sparc models are far more limited than newer models in how they check to see if a disk is bad. Disk 4 may have failed to respond in a reasonable amount of time or perhaps you saw another pattern?: http://kb.netgear.com/app/answers/detail/a_id/21437/~/what-does-this-light-pattern-mean%3F-(led) Newer models have a Disk Test boot option that can be used to help with checking if disks are bad. Unfortunately this option is not available for Sparc Handling of disk failures does improve over time. Updates to e.g. smartmontools can help as they add profiles for newer drives.

I have now received a replacement drive for the replacement drive. This time the replacement drive was good. As a reminder the ReadyNAS had locked up when a single drive failed and it was not indicating which drive failed or later apparently blaming the wrong drive (drive 4). In actuality there was a single bad block on drive 2. With this new replacement drive it did successfully do a factory default initialisation of the original drive 1, 3, and 4, with the new drive 2.

I have to confess I had not turned on email notification but as the entire ReadyNAS had locked up I am not sure they would have worked anyway. I have now turned on email notifications and tested them.

I still say there is absolutely no excuse for a RAID system to completely lock up with just a single drive failure. Drive 4 has worked as part of the latest factory default setup so drive 4 is apparently good. I have now checked the SMART status for all four drives including the new drive 2 and none of them and that includes the original drive 4 show any ATA or block errors.