Spare drive and copy back mode
A drive which is mounted separately from the drives for usual write and read operation, and when a failure occurs in a drive, data stored in the failed drive is copied to the spare drive so that the storage system can continue to be available equivalently to the original storage system. If the copy back mode is set to enable, when a failed drive recovered, data which has been copied to the spare drive returns to the recovered drive. If the copy back mode is set to disable, when a failed drive recovered, data which has been copied to the spare drive still exist in the spare drive. This mode can be set to a parity group basis.
The maximum number of spare drives that can be specified for each storage system is as follows:
Virtual Storage Platform G800 : 64 spare drives can be specified.
Virtual Storage Platform G600 or Virtual Storage Platform G400 : 32 spare drives can be specified.
Virtual Storage Platform G200 : 16 spare drives can be specified.