Disk does not exist

I have a TS-431 running 4.3.6.2805, I logged in this morning a found disk 2 did not exist according to storage manager. Nas did not report an error. I though the disk might have failed so I replaced the disk. disk 2 still not detected and now disk 3 is also listed as not existing. Now the NAS reports the error RAID has failed (understandably so) Is this a NAS rather than a disk error and if so is there anything I can do to recover the data

Always have backups…recovery should never be part of your strategy

Either buy a new migration compatible QNAP

Or contact a data recovery service…

Both more expensive than a backup would have been

It looks like this issue requires a more in-depth check and confirmation from our side. For data security reasons, our Support Team may contact you directly to assist further.