How does a RAID1 system determine which disk to use as the source and which disk to use as the destination when mirroring?
Assume for instance the following scenario: A RAID1 array is created with two disks A and B. A is replaced by disk C, which is added to the array. Files are beeing modified as time goes by. Now B is removed and A is reinserted.
Will the RAID1 system realize that A and C are out of sync? And that C is more up-to-date than A? And if not, is there a safe way to avoid the mirroring process to start immediately when disk A is inserted?
EDIT: I should clearify that in my scenario I assume that A had not failed when it was removed, and so, as far as I understand, neigther A nor C is "dirty" when the RAID1 system must decide which way to mirror between them. (And I assumed no bitmaps, but I understand this may be relevant.)