EMCMD <system> PREPARETOBECOMETARGET <volume letter>
This command should only be used to recover from a Split-Brain condition. It should be run on the system where the mirror is to become a target and is only valid on a mirror source. This command causes the mirror to be deleted and the volume to be locked.
To complete split-brain recovery, run CONTINUEMIRROR on the system that remains as the mirror source.
If volume F: is a mirror source on both SYSA and SYSB, you can use emcmd to resolve this split-brain situation. Choose one of the systems to remain a source – for example, SYSA. Make sure there are no files or modifications on SYSB that you want to save – if so, these need to be copied manually to SYSA. To re-establish the mirror, perform the following steps:
EMCMD SYSB PREPARETOBECOMETARGET F
The mirror of F: on SYSB will be deleted and the F: drive will be locked.
EMCMD SYSA CONTINUEMIRROR F
Mirroring of the F: drive from SYSA to SYSB will be established, a partial resync will occur (overwriting any changes that had been made on SYSB), and the mirror will reach the Mirroring state.