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General information about cloud server network volume backups

You can create backups of network volumes for cloud servers in two ways:

The service is powered by OpenStack Karbor and Cinder components.

Records of network volume backup operations are saved in audit logs.

You can view alternative ways of creating cloud server backups in the Backup methods table.

Full backup

A full backup is a complete reserve copy of a volume with all data.

Full backups can be created manually or automatically on a schedule by configuring a backup plan.

In the backup plan, you can configure a schedule for creating full backups by days of the week or using a cron expression. The plan settings also specify how many recent backups to keep.

Incremental backup

An incremental backup is a copy of the changes between the current state of the volume and the previous planned backup. This backup is created faster than a full backup and takes up less space because it stores only the changes on the volume.

Incremental backups can only be created automatically on a schedule.

Incremental backups are created daily at the time specified in the backup plan settings. A full backup is created first, and then it is performed once a week. On the remaining days, incremental backups are created.

Creating backups

We guarantee crash-consistent backups. At the time of creation, data on the disk is written to the backup. "Dirty data" generated when overwriting or deleting files on the disk can also be written to the backup. Data in cloud server memory is not written to the backup. Due to "dirty data":

  • the size of a full backup may exceed the actual size of data and files on the disk;
  • the size of an incremental backup may exceed the difference between the current data size and the size of the previous backup.

Creating a backup does not affect cloud server performance — all operations run on Selectel compute resources. When creating a full backup, a disk snapshot is taken, with no increase in load on the cloud server. When creating an incremental backup, changes between the current disk state and the previous backup are calculated on the fly, and the difference between the states is transferred to the backup storage.

Backup storage

By default, full and incremental backups are stored in three copies on a dedicated group of hardware:

  • in single-AZ pools, an isolated storage cluster is deployed in each pool segment. It stores backups and disks — this increases the speed of creating backups and restoring from them;
  • in the multi-AZ pool ru-6, a storage cluster shared across all pool segments is used. This allows you to restore a disk from a backup in any pool segment and with any disk type.

Such storage ensures data safety even in case of failures on servers hosting the disks.

A backup cannot be downloaded, but you can restore a disk from it — a new disk of the same type and size as the original will be created.

The ru-3 and ru-7 pools are connected by a multi-region backup system. When creating a backup manually for a network volume in one of these pools, you can select another pool to store this backup. Such a system allows you to create disaster-proof data copies.

Backups created automatically on a schedule are stored in chains of seven — one full and six subsequent incremental ones. The plan specifies how many full backups to keep (minimum is two). For example, if the plan settings specify keeping three full backups, the three most recent backup chains will be kept.

Backup storage limits

If backups are created automatically on a schedule, the total number of backups in a single project is unlimited. However, within a single plan, there is a creation limit: 90 backups for plans with full backups, and 14 full and 78 incremental backups for plans with incremental backups.

You can store up to 1,000 manually created backups in a single project.

Automatic backup deletion

For your information

Only for backups created automatically on a schedule.

In the plan settings, when choosing to keep recent backups, you specify how many recent full backups or chains of incremental backups to keep. When a new full backup is created for a disk, the service checks the total number of full backups of the disk within a single plan. If this number exceeds the maximum number specified in the plan, the oldest full backups are deleted.

Incremental backups are stored in chains of seven backups — one full and six subsequent incremental ones. A week after creating the first full backup, the earliest incremental backup is merged with the earliest full backup. If you specified keeping two full backups in the plan settings, the two most recent chains will be kept; if three full backups, the three most recent chains, and so on.

All backups will be preserved if you delete a disk, cloud server, or backup plan.

Backups can be deleted manually.

Cost

Backup storage is charged according to the Cloud Platform payment model.

Backup storage cost depends on the backup size and the pool segment in which it is stored. Only backups with the statuses AVAILABLE or RESTORING are charged; backups in other statuses are free of charge.

Every GB of backup storage is charged. If the backup size is less than 1 GB, the billable volume is rounded up to 1 GB.

note

For example, you store a 512 MB backup in the ru-9a pool segment. The backup storage cost will equal the cost of storing 1 GB in this pool segment — 4.02 ₽ per month.

The cost of one GB of backup storage can be viewed on selectel.ru.

You can view the actual backup size in the Control panel: in the top menu, click Products and select Cloud Servers → the Backups section → the Backups tab. You can also view the total billable backup volume in the Control panel: in the top menu, click Products → Cloud Servers → the Platform consumption section → the Current cost.