During DR testing via snapmirror on fas2040 pairs, we broke snapmirror relationship between primary and dr filers, data became available on DR filer snapmirrored volume, this failover works fine.
We made some new updates on DR volume. But when trying to failback from DR to Primary (primaryfiler*> snapmirror resync -S drfiler:dr_cifs1 primaryfiler:pri_cifs1), it failed to failback.
primaryfiler*> snapmirror resync -S drfiler:dr_cifs1 primaryfiler:pri_cifs1
primaryfiler: snapmirror.dst.resync.info:notice]: SnapMirror resync of pri_cifs1 to drfiler:dr_cifs1 is using drfiler(0142238385)_dr_cifs01.37 as the base snapshot.
Volume pri_cifs1 will be briefly unavailable before coming back online.
cifs open files prevent operation.
Snapmirror resynchronization of pri_cifs1 to dr_cifs1 : revert to resync base snapshot failed
Aborting resync.
primaryfiler*> [primaryfiler: replication.dst.resync.failed:error]: SnapMirror resync of pri_cifs1 to drifiler:dr_cifs1 : revert to resync base snapshot failed.
We discovered that during failover time, because we just run snapmirror break to stop the snapmirror without really shutdown the entire Prod site, therefore Primary site volume was still continuely receiving I/O or updates from applications and users, means primary site also has new updates while snapmirror was broken.
We could resync the original snapmirror (from Primary to DR) without any issue, updates on DR are deleted as expected.
My question is, for the DR testing like this (both DR and Primary sites have new updates during broken snapmirror), how can I failback from DR to Primary with
1. just keep DR updates and delete Primary updates?
2. keep both DR and Primary updates that was got written to their own vol during snapmirror broken?