RAID Failure Simulator

Click drives to fail them. The simulator shows whether the array survives, how much redundancy is left, how long the rebuild would take, and the URE risk during recovery — the same math as our rebuild calculator.

Your array

RAID level

Drive class

Drives×

Drive sizeTB

Rebuild speedMB/s

Click a drive to fail it

What happens now

How this is calculated

Fault tolerance per level: RAID 5/RAIDZ1/SHR-1/Unraid-1P = 1, RAID 6/RAIDZ2/SHR-2/Unraid-2P = 2, RAIDZ3 = 3, RAID 1 = N−1, RAID 10 = 1 per mirror pair. Rebuild time = drive size / speed. URE probability = 1 − exp(−rate × bits read), same model as the rebuild calculator.

Takeaway: If the simulator scares you at your real drive count, that's a signal. Full analysis in what happens when RAID fails →