Migrated exchange from 2003 to 2010 on a repurposed box during the summer.
We’re having issues with exchange backing up and it looks like it might be due to storage problems.

So I’m looking into it and have come across some ‘inconsistencies’ with the RAID array.

Pretty sure I built the array as RAID 5, it seems the go-to option generally.
The array consists of 4 x 147Gb 15k SCSI Drives.
The RAID is reported as 420Gb in size, both in the configuration utility and in Windows, which seems right as the drives are in actuality 140Gb and 3 x 140 is 420

But the configuration utility tells me the array is RAID 0 and is not ‘REDUNDANT’ (as per RAID level 0)

That doesn’t tally up with the logical disk size.

One of the drives shows 3 media errors, so I intended installing a fifth drive (hot spare) and failing the dodgy drive. But when I did so the array went offline (which tallies with RAID 0)

How can I be sure what I have?

Can I add a fifth drive and move from RAID 0 to RAID 5 ‘live’ or do I need to recreate the array from scratch?