Virtual Server Backups

A Backup is a snapshot of a virtual server disk moved to an off-site location.

Access Permissions  
SuperAdmin read-write
DCAdmin read-write
VmOwner read-only

Backups Parameters

  • Name - Backup name (read-only).

  • Disk ID - Virtual server disk ID (read-only).

  • Type - Backup type (read-only). One of:

    • Dataset
    • File
  • Created - The date and time when the backup was created (read-only).

  • Status - Backup state (read-only). One of:

    • ok
    • pending
    • restore
    • lost
  • Duration - The amount of time spent to create the backup (read-only).

  • Size - The size of the backup (read-only).

  • Note


Backups created with the Freeze filesystem option enabled are marked with a flag icon appended to their status.

Backup Actions

  • Backup now - Immediately start a backup process based on a backup definition.

  • Delete backup - Remove data of the backup.

  • Restore backup - Restore server disk data from the backup to the existing virtual server disk or a disk of an another virtual server.


    A backup restore results in all data loss on the target virtual server and disk, including all virtual server’s snapshots.


Backing up many virtual servers at the same time can have a high impact on the I/O load of the affected compute and backup nodes, potentially causing short or even long-term unavailability of services. A fair distribution of backup schedules in time can easily eliminate this problem. A backup definition overview of a particular virtual data center or backup node can be obtained via the compute node backup definition view or API:

user@laptop:~ $ es get /vm/define/backup -dc admin -full --tabulate

user@laptop:~ $ es get /node/ -full --tabulate

Backup Definitions

A Backup Definition is a configuration based on which periodic backups are automatically created and deleted.

Access Permissions  
SuperAdmin read-write
DCAdmin read-write
VmOwner read-only

Backup Definition Parameters

../../_images/backup_definition_update.png ../../_images/backup_definition_update_advance.png
  • Name - Backup definition name.

  • Disk ID - Virtual server disk ID.

  • Backup type - One of:

    • Dataset - Backups are created by using ZFS datasets in an incremental way (optimal and recommended).
    • File - Backups are created by storing full ZFS datasets into files (can be used to store backups onto remote data storages connected via NFS or Samba).
  • Backup node - Compute node with backup capabilities enabled.

  • Storage - Name of the node storage on the chosen backup node.

  • Schedule - Automatic scheduler configuration in Cron format. Use your local time for the hour field (it will be internally converted into UTC).

  • Retention - Maximum number of backups to keep. After exceeding this number of backups the oldest backup associated with the backup definition will be automatically removed.

  • Active - Whether the backup definition is active.

  • Description

  • Compression - Compression of File backups. One of: off (no compression), gzip (fast compression), bzip2 (more effective compression).

  • Bandwidth limit - Backup speed limit in bytes per second.

Advanced Backup Definition Parameters

  • Freeze filesystem? - Whether to create application-consistent backups (KVM only). Requires QEMU Guest Agent to be running inside the virtual server.

Cron Format

Cron format is a flexible way to define time and frequency of running a periodic task. It is defined as a string of five fields separated by a space.

Field name Allowed values
Minutes 0-59
Hours 0-23
Day of month 1-31
Month 1-12 (January - December)
Day of week 0-6 (Sunday - Saturday)


  • 30 08 10 06 * - Run a task once every year on June 10 at 8:30 AM.
  • 00 11,16 * * * - Run a task twice a day at 11:00 AM and 4:00 PM.
  • 00 09-17 * * * - Run a task once every hour between 9:00 AM and 5:00 PM.
  • 00 09-18 * * 1-5 - Run a task once every hour between 9:00 AM and 5:00 PM from Monday till Friday.
  • * * * * * - Run a task once every minute.
  • 0,10,20,30,40,50 * * * * - Run a task once every 10 minutes.
  • 0,2,4,6,8,10 * * * * - Run a task every 2 minutes during the first 10 minutes of a hour.
  • 0 0 1 1 * - Run a task once a year at midnight of January 1.
  • 0 0 * * * - Run a task once a day at midnight.
  • 0 * * * * - Run a task once an hour at the beginning of the hour.