Summary

An administrator may notice an alert in the Zerto GUI regarding the Journal Hard Size limit being reached and Journal History might be reduced. This article explains further information on the Hard Size limit as well as how to resolve it.

Symptoms

1. The below alert will be displayed in the Zerto GUI:

The {journal} journal for VM {vm_name} in VPG {vpg_name} has reached its configured limit of {x}. Older checkpoints might be removed and the journal history might be reduced to make space for new data.

2. VPG enters bitmap sync; VPG sync slows down no matter it is in Initial, Delta, or Bitmap Sync.

Root Cause

When creating a VPG, there's a value that can be set to limit the journal maximum size (the hard limit).
The default value is 150Gb. When the journal size hard limit is reached, then the old checkpoints will be promoted to the recovery disks and new checkpoints will be written.
This will cause the journal not to be populated with the number of checkpoints it should have (according to the SLA set by the administrator).

For example:

Journal is set for 4 hours.
Journal size limit is set to 50GB.
After 30 minutes the hard limit is reached and old checkpoints are being applied to the recovery disks meaning the journal contains 30 minutes worth of checkpoints.

The hard size limit is either reached because:

  1. The attribute itself was not set properly based on the typical change rate of the protected VM, or,
  2. The change rate of the protected VM has increased suddenly/unexpectedly.

Solution

To relieve the alert:

  1.     

    Increase the Journal Hard Size limit via Edit VPG -> Replication -> VM Settings.

        
  2.     

    Click Done.

        

To determine the cause of why the threshold was crossed:

  1.     

    Check with application owner of suspect VM to determine sudden increase of change data.

        
  2.     

    Utilize Planner in Analytics if #1 did not provide any evidence into a potential increased workload/if the hard size was too low to begin with.

        
  3.     

    If no change in application change rate and Planner reports back similar numbers, kindly collect a log bundle and engage Zerto Support for further assistance.