Hi Bob, thanks for your reply.
In fact, while there were no problems identified by the Media Scan, the status of the RAID was listed as Degraded. I have 7x 1TB Seagate Constellation ES drives in my Raid, setup at RAID5.
I was told by ATTO tech support that one of my drives had failed months before, and for some reason another of the drives briefly went offline and then came back on again, which probably caused the failure – but I’m at a loss to explain why it had been working perfectly well one day then completely offline the next…
I have now rebuilt the RAID (at RAID6 this time!!) because 95% of the data was backed up anyway – but if you think you could shed some light on what may have gone wrong that would be greatly appreciated!
Many thanks,
Chris