I have a RAID10 (8x1TB) array on a 3ware 9690 card running on an Ubuntu 1110 server.

There was a kernel update so I scheduled a reboot after which the array was inaccessible. I checked the status a drive has died in the array, but the controller has thrown the entire array into an 'inoperable' state instead of simply degraded (what's the point of the RAID now ;-).

After taking out the 'dead' drive I run a quick test to find it completely functional without a bad sector to be found.

I try to put the drive back in but the array still marks the disk as degraded (remembering serial number or something??) and the entire array as inoperable...

So I swap it out for a known working drive (not the same capacity but higher - should still work) and initiate a rebuild with the the new drive as a replacement. This fails instantly with the error "(0x0B:0x0033): Unit busy : Failed to start Rebuild on Unit 0". The unit shouldn't be busy as it is not mounted (the card itself is listed with lshw but the array it provides is not).

I'm pretty much at an impasse now, I don't understand how I can have a single drive failure on a RAID10 that makes the entire array inaccessible, degraded I could understand but inaccessible?? I don't think the controller as prior to the reboot it was completely functional.