Fast Recovery

This function recovers data quickly by relocating data in the failed drive to the other remaining drives when a drive error is detected.

For a RAID group that is configured with RAID6-FR, Fast Recovery is performed for the reserved area that is equivalent to hot spares in the RAID group when a drive error occurs.

If a second drive fails when the reserved area is already used by the first failed drive, a normal rebuild (hot spare rebuild in the ETERNUS DX) is performed.

For data in a failed drive, redundant data and reserved space are allocated in different drives according to the area. A fast rebuild can be performed because multiple rebuild processes are performed for different areas simultaneously.

Figure: Fast Recovery

Caution

For the Fast Recovery function that is performed when the first drive fails, a copyback is performed after the failed drive is replaced even if the Copybackless function is enabled.

For a normal rebuild process that is performed when the reserved space is already being used and the second drive fails, a copyback is performed according to the settings of the Copybackless function.