[mnorth]

Thanks for the advice. I could not get the RAID migrate to work selecting both drive 6 and 7 at the same time, only one. So I started with one new disc.

But, it did not go as planned. I have the latest firmware, but during the migrate (after nearly 20 hours!) the 7700 started beeping, the display showed Degraded RAID, and I could not access the RAID status via the web interface.

I restarted the device and it came up with no RAID at all (all data lost but I have a back-up). So now I am formatting a RAID to the full capacity from scratch - and ETA is under 5 hours. There were no logs to show what had happened.

So, I conclude that its quicker and safer to start from scratch rather than trying to migrate a RAID.

And it shows how important it is to back-up the date before fiddling with the RAID.