How would I go about doing a 100% data swap between two storage devices of identical size and keep both data partitions without using a third device as a temporary buffer?
In other words, I have two VERY large storage arrays each with two identically sized VERY LARGE volumes as such:
DRIVE 1: VOLUME A
DRIVE 2: VOLUME B
I want the data from volume a to go to volume b and the data from volume b to go to volume a. All data must be preserved. I have no means of obtaining a third device for temporary storage.
I figure that theoretically this is possible to program at the bit level. As long as there is some free space on both volumes (which there is), that free space can serve as temporary storage for swapping data. Worst case, I can just do this manually by doing a batch copy of directories. However, surely there must be software that does this at the bit level?
Unfortunately I have scoured the net and came up empty. All the software I see does CLONING of an old drive to a new one, but no direct bi-directional volume data swap.
** Update **
Just to be clear - I realize that it's possible to move data around manually into multiple temporary locations and use the backup/restore process. That's what I'm trying to avoid having to do because of the time and effort involved in restoring the data from multiple locations and through multiple processes. There just isn't any other array large enough to serve as a temporary location for the entire set of data/files.
** SOLUTION **
I ended up manually swapping data back and forth since the data sets were modular. The Altap Salamander file manager has the ability to queue file transfers so I basically created a queue of file transfers back and forth with sizes calculated to the amount of free space that would be available on each drive after a set of files copied. Worked like a charm but way too time consuming vs just using a spare storage array to temporarily house an entire copy. Would be cool if there was software that automatically did this, but clearly it's one of those problems where extra hardware beats a software solution.