How does snapmirror's DelayedUpdate work?
Applies to
ONTAP 9
Answer
- No matter what the reason makes snapmirror's
ScheduledUpdate
becomeDelayedUpdate
,DelayedUpdate
will start as soon as the transfer status becomes available. - If multiple scheduled updates are delayed, the middle scheduled updates might be skipped, and only the current latest ones can be continued to start.
- ONTAP uses
DelayedUpdate
logic to restart the aborted transfer due to Takeover/giveback as below.
Delete old snapshots -> Restart previous incomplete snapshots transfer -> Transfer new snapshots
Additional Information
- When does a SnapMirror retry or not retry upon takeover and giveback?
- Does aborted SnapMirror try to transfer again by takeover or giveback?
- Snapmirror update is unintentionally triggered after Takeover/Giveback
- ONTAP upgrade triggers SnapMirror DelayedUpdate
- Delayed update does not work for manual update, works only for scheduled update.