recovering a RAID 1 array with a single disk failure
The theory is that the data is all on the good disk, and when a replacement disk is installed, it should rebuild the mirror.
However, the practical reality is that it will depend very much on the implementation and specifics of the particular unit, such as whether it supports hot-swappable disks or not and whether it has to be taken off-line for recovery to occur. Performance would be degraded while rebuilding is done, even if on-line.
SD