The disk format of an OpenVZ container typically refers to the filesystem type used by the container. Currently, OpenVZ supports the following three filesystems:
1. SIMFS: A legacy file system that’s similar to a directory within the host system’s file system. It does not support disk quotas.
2. PLOOP: A modern, more efficient filesystem that treats a VM as a single file, stored as a chunk of consecutive blocks on the hard drive. It supports live migration and snapshots.
3. EXT4: The fourth extended filesystem is a journaling file system for Linux, developed as the successor to ext3.
To change the disk format, you might need to create a new container with your desired filesystem, and then migrate your data.
However, there isn’t any direct way to change the filesystem once the container is created. To do, follow the steps below:
1. Back up your data. Use the ‘vzdump’ utility to create a backup of your current container.
E.g., ` vzdump —dumpdir /path/to/backup/directory/ 101`1. Create a new container with desired filesystem. Use the ‘vzctl’ utility to create a new container with the desired filesystem. Specify the ‘—layout ploop’ option for a ploop file system or ‘—layout simfs’ for a simfs filesystem.
E.g., `vzctl create 102 —ostemplate centos-6 —layout ploop`1. Restore your data. Use the ‘vzrestore’ utility to restore the data from your backup to the new container.
E.g., `vzrestore /path/to/backup/directory/Please note that the above commands might vary depending on your exact OpenVZ setup and require root permissions to run.
Also, before you begin, make sure you have enough available storage in your backup directory and for the new container.
