Article number
000003306
Affected Versions
All
Source Hypervisor
All
Target Hypervisor
All

Problem with Older Checkpoints in Journal Having Larger Gaps Between Each Checkpoint

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Summary

An administrator may notice in the Failover/Move/Offsite Clone wizards that the further back into the journal's list of checkpoints available, that the checkpoints themselves appear to be less frequent even with a consistently healthy RPO.

Root Cause

When a VPG is fully synced, checkpoints are recorded every few seconds in the journal.

After a while, the number of checkpoints available from which to choose a recovery point can be in excess of thousands per VPG.

When this threshold is reached, in order to enable efficient management and use of the checkpoints, the number of checkpoints is diluted with respect to time, as follows:

  • Within the latest 2 hours: All of the checkpoints are available for recovery.

  • Between 2 and ~4.5 hours: There are about two to three checkpoints every 15 minutes.

  • From 4 hours and over: 1 checkpoint is kept every 15 minutes.

The dilution of checkpoints is for optimization for the ZVM database and GUI improvements based on the assumption that the administrator does not need a finer granularity over a longer time frame and that the given Journal History is healthy.

Note: Checkpoints which are either added manually, added via the ZertoVssAgent, or marked as part of a Failover Test, are not diluted.

Symptoms

The checkpoint selection within a DR Operation, such as Failover, will show all checkpoints available, however, the older checkpoints are spaced out further from one another versus the latest checkpoints which would only be spaced out as far as the current RPO.

Solution

This is an expected feature of the Zerto product so there are no steps to resolve this.