RAID 5 Data Recovery

RAID 5 is the most common array type in business servers and NAS devices. Data and parity are distributed across three or more drives, so the array survives one drive failure.

When a second drive fails – or a drive with bad sectors is hit during a rebuild – the array goes offline. With today’s large drives, rebuilds take many hours or days, which increases the chance of a second failure. This is the most common RAID case we handle.

Common RAID 5 Failures

• Two drives failed, or one failed during the rebuild
• Array degraded for months without anyone noticing, then a second disk fails
• Wrong drive removed or replaced
• Controller failure or lost configuration
• Re-initialised array or recreated volume
• Ransomware encrypting the server’s file shares

How We Recover a RAID 5 Array

RAID 5 recovery depends on four parameters: disk order, stripe size, parity rotation (left or right, synchronous or asynchronous) and any parity delay used by the controller. We determine these from the data itself, then identify any disk that dropped out of the array earlier – its data is out of date and must be excluded. With one member excluded or unreadable, the missing blocks are regenerated from parity, producing a consistent virtual volume from which we recover your files.

Before You Do Anything

See RAID & server data recovery for the servers, controllers and NAS systems we support.

Frequently asked questions