Article number
Affected Versions
Source Hypervisor

Syncing to Azure on 8.0u1

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Root Cause

In 8.0u1, a location change was made for an existing API call responsible for Zerto’s VRA optimization. The call allows Zerto to understand the highest offset of data occupied in the disk. The location change was problematic because in certain situations the call can take too much time and cause a timeout to a mirror activation process while other mirror activations are waiting in line. This issue has been fixed with the release of 8.0u1p1.


After an upgrade to 8.0u1, the following symptoms may occur:

  • RPO of all VPGs rise with no active syncs
  • VRA service crash



Upgrade to Zerto for Azure version 8.0u1p1.


Customers already on 8.0u1: Disable the highest offset validation by setting tweak t_disableSkipZeroIoInAzure=1 on the ZCA. This can be performed through the tweaks file or by logging into myZerto Support Portal and opening a case with Zerto Support for assistance.