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How to Create Application Consistent Snapshots for VMware

In some cases, the VMware VSS writer does not create application consistent snapshots on some virtual machines (VM). As a result, the backed up data may not be in an application-consistent state.

Verify Prerequisites:

Complete the following prerequisites to create application consistent snapshots:

• Latest VMware tools must be installed in the VM.
• The VM must run on ESXi 4.0 or later.
• The VM must use only SCSI disks. The VM must have equal number of free SCSI slots to match the number of disks.
• Application consistent quiescing is not supported for VM that have IDE or SATA disks.
• All volumes in the VM are basic disks and there are no dynamic disks.
• The VM guest OS does not have storage spaces enabled.
• The disk.EnableUUID parameter of the VM must be enabled. VMs created on 4.1 or later have this parameter enabled by default. The following configurations are performed automatically by backup job to avoid data inconsistency and perform application-consistent backup. If backup job cannot enable disk.EnableUUID due to some reasons, configure the parameter manually using the following procedure:
  • If disk.EnableUUID exists and is FALSE, change it to TRUE.
  • If disk.EnableUUID does not exist, create it and set it to TRUE.
  • If disk.EnableUUID exists and is TRUE, keep it as it is.

    Note: For more information about creating application-consistent backup, see the VMware KB article.

Affected Features:

If any of the requirements are not met, the session data remains crash consistent. As a result, the following features are affected:

• Backed up data that includes application data of a VM, such as SQL, Exchange, and SharePoint, may remain in a crash consistent state.
• Catalog job may fail.