vRanger 7.7 - User Guide

Physical backup transport options

Physical backup transport options

vRanger transports describe only how data is read from the source server, not how the data is sent to the repository. When backing up physical servers, the vRanger client reads the data directly from the disk and sends data from the source server to the repository. Depending on how the source server is connected to the repository, this process can result in network backups or LAN-free backups. For backups to be LAN-free, the source server and repository must exist on the same SAN.

When performing backups of physical servers, or backup groups containing physical servers, the Transport Selection portion of the Backup Wizard is not shown, as there is only one available option.

Determining application consistency

Determining application consistency

The levels of, and methods for providing, application consistency differ between VM backups and backups of physical servers. For more information, see the following topics:

•	Application consistency for virtual backups

•	Application consistency for physical backups

Application consistency for virtual backups

Application consistency for virtual backups

vRanger provides various levels of protection for VMs. The means that each level uses to accomplish its task depends on the type of VM being protected.

•	Application consistency for VMware VMs

•	Application consistency for Hyper-V VMs

Application consistency for VMware VMs

Application consistency for VMware VMs

By default, vRanger does not provide quiescing during backups. When you enable the Enable Guest Quiescing option, quiescing in vRanger is provided by leveraging the VMware® Tools installed in the VM.

This feature can provide three different levels of backup consistency:

•

Crash consistent: A crash-consistent backup is analogous to pulling the plug on a server and then backing up the data. The state of the data that is being backed up with respect to the users of the data is indeterminate. Restoring a crash-consistent image is equivalent to rebooting a server after a hard shut-down.

•

File-system consistent: File-system consistency is achieved through standard quiescing by using the VMware Sync Driver, which ensures that no file-system writes are pending when the snapshot is taken. For normal VMs, file-system consistency is adequate, although it can cause corruption in database applications.

•	Application consistent: Consistency of VSS-compatible applications is achieved by freezing application I/Os prior to creating the VM snapshots. This option ensures that all application writes requests in the machines memory are committed to disk before the snapshot is taken.

The level of consistency provided by the Enable Guest Quiescing option depends on the version of VMware® ESXi™ — and the corresponding VMware Tools — and the guest operating system. The following table provides more detail on what is needed to achieve various levels of consistency:

 

Table 1. Achieving consistency

File-level quiescing
	ESXi 6.0	ESXi 6.5	ESXi 6.7
Windows Server 2008 R2 SP1	VMware VSS	VMware VSS	VMware VSS
Windows Server 2012 Windows Server 2012 R2	VMware VSS	VMware VSS	VMware VSS
Windows Server 2016	VMware VSS	VMware VSS	VMware VSS
Application-level quiescing
	ESXi 6.0	ESXi 6.5	ESXi 6.7
Windows Server 2008 R2 SP1	vzShadow.exe	vzShadow.exe	vzShadow.exe
Windows Server 2012 Windows Server 2012 R2	vzShadow.exe	vzShadow.exe	vzShadow.exe

As shown in the preceding table, application consistency is not always available with the basic quiescing options. In these situations, you may use the vRanger VSS Tools — vzShadow.exe — for application-level consistency.

IMPORTANT: Due to the database architecture, vRanger cannot take application-consistent backups of vCenter Server Appliance (VCSA) VMs. Use caution when backing up a VCA VM to ensure reliable recovery.