Don't start another rebuild
A rebuild onto the wrong disk, or with the drives out of order, writes parity over good data. That's the one mistake we can't always undo.
Shut the array or NAS down cleanly and leave it off. Don't initialise, re-create or 'repair' the volume.
Why the second drive failed
Drives bought together tend to wear out together. When one fails, its neighbours are often close behind, and a rebuild reads every sector of every drive. That's exactly the moment a second weak drive gives out.
Label every drive
Leave the drives in their bays if you can. If they're already out, label each one with its bay number. Bring every drive, including the ones marked failed and any drive that was replaced earlier.
Have this handy
- NAS or controller model, number of drives and RAID level, if you know them.
- Which drive failed first, and whether a rebuild started or finished.
- Which shares, databases or virtual machines you need first.
Don't run repair tools on the volume
File system repair tools write to the volume. On one pair of video arrays we recovered, a disk repair utility had already been run before they reached us and had overwritten the catalog, the index of every file and folder. The recovery still worked, but it was harder than it needed to be.
What we do with it
Every drive is labelled and copied in full; any failing drive is repaired first so it can be read. Drive order, stripe size and parity are worked out from the data on the disks, and the array is rebuilt from the copies. Your original drives are never written to.
Multi-drive arrays need more work to assess, so the evaluation is quoted before we start. If the volume was encrypted, recovery is possible only with the password or key.
Bringing it in
Drop it off at #610 - 11012 Macleod Trail SE, Calgary, with no appointment needed: Monday to Thursday 8:00 AM to 6:00 PM, Friday 8:00 AM to 5:30 PM. Outside Calgary, call (587) 387-2346 for packing instructions before you ship it; how it's packed matters.