ISSUE
For host-level backups of VMware, AHV, and XenServer VMs, quiesce settings determine how the VM is brought to a consistent state in preparation for backup. (Quiesce settings do not apply to Hyper-V VMs.) Unitrends provides these quiesce settings: crash consistent, application consistent, and application aware. Detailed descriptions of each setting are described in the table below.
Consider the following when working with quiesce settings:
• For appliances that were deployed with release 9.1 or later, crash consistent is the default quiesce setting for newly added virtual hosts and VMs.
• For appliances that were deployed with a pre-9.1 release, application consistent is the default quiesce setting for newly added virtual hosts and VMs. The application consistent default persists upon upgrading to later releases.
• The application aware setting must be applied to VMs individually. Applying a quiesce setting globally or to one host's VMs does not overwrite a VM's application aware quiesce setting. A VM's quiesce setting is overwritten only if it was set to crash consistent or application consistent.
• Backups are run using a cascading fall-back approach. If a backup attempt fails, the appliance tries again with a less stringent quiesce setting:
– Application aware falls back to application consistent.
– Application consistent falls back to crash consistent.
– If crash consistent fails, the backup fails. (There is no fall back.)
– For VMware and AHV, a backup that was run with a lesser quiesce setting is marked with a Warning status.
– For XenServer, a backup that was run with a lesser quiesce setting is NOT marked with a Warning status.
– To determine which quiesce setting was used, go to the Backup History report and select the backup. Detailed messages display in the Backup Status window. Look at the Snapshot for this Backup was created with... entry in the vProtect Messages, aProtect Messages,or xProtect Messages section.
|
Quiesce setting |
Description |
Apply globally to all VMs |
Apply to one host's VMs |
Apply to selected VMs |
|---|---|---|---|---|
|
Crash consistent |
The VM is not quiesced before the backup runs. The backup takes a snapshot of the VM disks in their current state. This is the fastest quiesce setting. |
Apply to newly discovered VMs by selecting Crash Consistent in the Global Virtual Machine Settings dialog. Optionally, use Apply to all current VMs to apply to existing VMs. For details, see To manage global quiesce settings. |
To apply to one host's VMs, select Overwrite this hypervisor's VMs to Crash Consistent in the Edit Virtual Host dialog. For details, see To apply a quiesce setting to one host's VMs. |
To apply to one or more selected VMs, select Crash Consistent in the Edit Assets dialog. For details, see To edit a virtual machine asset. |
|
Application consistent |
The VM guest operating system invokes processes to flush application and filesystem transactions and place the VM into an idle state while a VM disk snapshot is taken. |
Apply to newly discovered VMs by selecting Application Consistent in the Global Virtual Machine Settings dialog. Optionally, use Apply to all current VMs to apply to existing VMs. For details, see To manage global quiesce settings. |
To apply to hosted VMs, select Overwrite this hypervisor's VMs to Application Consistent in the Edit Virtual Host dialog. For details, see To apply a quiesce setting to one host's VMs. |
To apply to one or more selected VMs, select Application Consistent in the Edit Assets dialog. For details, see To edit a virtual machine asset. |
|
Application aware (VMware Windows VMs only) |
Use this option for application-aware protection of hosted Exchange or SQL simple recovery model applications. Leverages VSS writers to provide application consistent quiesce and additional post-backup processing. Exchange logs are truncated with VMware full and incremental backups. SQL logs are not truncated. See Recommendations for protecting SQL databases hosted on VMware virtual machines for best practices. |
Not applicable. Must be applied to VMs individually. |
Not applicable. Must be applied to VMs individually. |
Apply to one or more selected VMs. To set up application-aware protection, use the Edit Assets dialog to supply administrative credentials and to select the Application Aware quiesce setting. For details, see Using application aware quiesce. |
Detailed descriptions of each quiesce setting are given in the following table: