network volume backups
You can backup network volumes of cloud servers in two ways:
- configure automatic scheduled backups. Create a backup plan, specify a backup schedule and add network disks to the plan — see Configure scheduled backups for details. You can configure scheduled full or incremental backups;
- manually — commit the system state and store the backup remotely from the disk. You don't need to configure a plan to create a manual backup — see Create a manual backup for details. Only full backups can be created manually.
The service is powered by OpenStack Karbor and Cinder components.
To see alternative ways to back up cloud servers, see the Backup Methods table.
Full backup
Full backups can be created automatically on a schedule and manually.
A full backup is a complete backup of a disk with all data.
You can customize the schedule for creating full backups by day of the week or via cron-expression. The plan settings specify how many recent backups to keep.
Incremental backup
Incremental backups can only be created automatically on a schedule.
An incremental backup is a copy of the changes between the current disk state and the previous backup created by the plan. This backup is faster than a full backup and takes up less space because it only stores changes on disk.
Incremental backups are created daily at a time that is specified in the backup plan settings. A full backup is created first, then it is created once a week. On other days, incremental backups are created.
Taking backups
We guarantee crash-consistency copies — only the data that was on the disk at the time of backup will be written to the backup. All data that was in the cloud server's memory at that moment and not on disk will not be written to the backup.
Taking a backup does not affect the performance of the cloud server — all operations take place on Selectel's computing power.
Creating a full backup creates an instant snapshot of the disk from which the backup is taken — with no load growth on the cloud server.
When an incremental backup is created, the 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 store.
Backup Storage
Full and incremental backups are stored in Ceph storage — a cluster is deployed in each pool segment. Both backups and disks are stored in the same cluster — this increases the speed of taking a backup and restoring from it.
Backups are stored on separate servers in three copies — this will save data if there is a problem with the servers where the disks reside.
The backup cannot be downloaded, but from it you can restore disk — a new disk of the same type and size as the original one will be created.
Backups that are automatically scheduled are stored in chains of seven — one full and six subsequent incremental backups. The plan specifies how many full backups to keep (minimum is two). For example, if the plan settings specify storing three full backups, the last three backup chains will be stored.
Backup Storage Restrictions
If backups are created automatically on a schedule, the total number of backups in one cloud platform project is unlimited. At the same time, there is a limit on creation within a single plan: for plans with full backups there are 90 backups, for plans with incremental backups there are 14 full backups and 78 incremental backups.
A maximum of 1000 manually created backups can be stored in one project.
Automatic deletion of backups
Only for backups that are created automatically on a schedule.
The plan settings specify how many recent full backups or incremental backup chains 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 the same plan. If this number is greater than the maximum number specified in the plan, the oldest full backups are deleted.
Incremental backups are stored in chains of seven backups — one full backup and six subsequent incremental backups. One week after the first full backup is created, the earliest incremental backup is merged with the earliest full backup. If you specified in the plan settings to store two full backups, the last two chains will be stored, if three full backups, the last three chains will be stored, and so on.
All backups are retained if you delete a disk, cloud server, or backup plan.
Backups can be deleted manually.
Cost
The cost of storing backups depends on the size of the backup and the pool segment in which it resides.
Backup storage is paid for by cloud platform payment model.
Paid for each GB of stored backups with statuses AVAILABLE or RESTORING. Backups in other statuses are not paid for.
The cost per GB of backups can be viewed at selectel.ru.
You can view the actual backup size in dashboard under Cloud Platform → Backups → Backups tab. To see the total amount of backups that are paid for, see Cloud Platform → Platform Consumption → Current Cost tab.