BackPressure Duration and Bitmap Mode Alarm

This article applies to all JSDR software versions.

Alarms are sent by the MSA if either of the following conditions occur:

Backpressure

“Backpressure On Frequency” is measured as the percentage of operating time application write operations were slowed to accommodate data replication.

Backpressure Alarm

• An alarm notification will be triggered if application write Backpressure has been applied for a period exceeding 5 consecutive minutes.

Cause of Backpressure

• Backpressure occurs when the replication incoming data rate exceeds the outgoing data rate.

Note: To monitor backpressure, the network statistics of protected VMs and DRVAs can be verified from the vCenter level to isolate any issues.

Bitmap

“Bitmap On Frequency” is measured as the percentage of operating time data could not efficiently reach the DRVA causing newly written data to be captured by the IO Filters in bitmaps for replication at a later point in time.

Bitmap Alarm

• An alarm notification will be triggered if a domain stays in bitmap mode for a period exceeding 5 consecutive minutes. 

Cause of Bitmap Mode

• Bitmap mode occurs when:
  • There is a network disruption between the DRVA and the object store.
  • When the replication log is full and cannot be written to.

Note: DRVA network statistics can be checked from the vCenter.