mdadm, bitmap and split-brain

Hi,

I'm wondering, in the case of raid1 array with internal bitmap, it goes like this :
1. Machine A has 1 raid1 array with Disk1 dan Disk2
2. Dettach Disk2 from Machine A, put it on Machine B
3. Machine A runs normally, Machine B runs on normally on different place.
4. Detach Disk2 from Machine B, put it back on Machine A, re-add Disk2 to md1

If this were raid1 without bitmap, Disk2 will be overwritten from scratch with contents of Disk1, what happen if the array has bitmap ? Would there be partial sync ? Would the two disk be identical with only using partial sync ?

It might fail to re-add, or it might do a partial resync and probably leave the two devices different so corruption would likely appear.

Just don't do this. If you want to use disk2 on a different machine, assemble it with
--update=uuid
the first time so it gets a different uuid and can never become confused with the old array.

NeilBrown