Linux Backup
ImplementationLast Updated December 16, 2024
On Linux virtual machines, VMware supports
only crash-consistent backups, however application-consistent backups are
possible through the use of customer pre-freeze and post-thaw scripts.
Two methods are attempted sequentially when a
quiesced snapshot is requested of a Linux virtual machine:
- Using theioctl(2) mechanismsFIFREEZEandFITHAWbuilt into the Linux kernel.This option is available in only with kernel versions newer than 2.6.32 on Linux virtual machines running VMware Tools 5.x or higher (vSphere 5.0 and later).
- Using thesync(2) system call.The first method allows you define custom scripts that get called by VMware Tools before and after quiesce. Here are two commands that can be called from pre-freeze and post-freeze scripts:The mount point used in the scripts (root in the examples above) must be mounted with thenoatimeoption, meaning do not updateinodeaccess times on the file system, for freeze and unfreeze to work.