[Yandex Cloud documentation](../../index.md) > [Yandex Compute Cloud](../index.md) > [Concepts](index.md) > Disks and file storages > Disk snapshots

# Disk snapshots


In Yandex Cloud, a _disk snapshot_ is a copy of the disk file system made at a certain point in time.

You can use disk snapshots for various purposes, e.g.:

* Migrating data from one disk to another, for example, to a disk in a different availability zone.
* Creating a disk backup before performing operations that may damage your data.
* Disk versioning by creating snapshots on a regular basis.

{% note info %}

If you need to create multiple disks with the same content, you can use [images](image.md). Creating disks from images is faster than doing so from snapshots.

{% endnote %}

A disk snapshot only contains the data that was written to the disk at the time its snapshot was created. If the disk is attached to a running VM, the OS and app cache will not be included in the snapshot. For more on how to prepare a VM for a disk snapshot and ensure snapshot data integrity, see [this guide](../operations/disk-control/create-snapshot.md#prepare).

You can create disk snapshots both manually and automatically, based on a [schedule](snapshot-schedule.md).

A single snapshot can only be created for one disk at a time.

Each snapshot will get assigned a particular [virtualized hardware generation](hardware-generations.md) on which a VM instance can be deployed from this snapshot. You can assign a particular hardware generation to a snapshot only at the time of creating it.

Once a snapshot is created, you cannot change the generation assigned to it. Instead, you can [recover](../operations/disk-create/from-snapshot.md) the current snapshot to a new [disk](disk.md) and then [create](../operations/disk-control/create-snapshot.md) a new snapshot from that disk with another hardware generation assigned.

You can create snapshots of network [disks](disk.md#disks_types) and drives, such as HDDs, SSDs, and non-replicated SSDs, as well as ultra high-speed network storages with three replicas (SSD).

For non-replicated SSDs and ultra high-speed network storages with three replicas (SSD), the snapshot time is not determined.

To create snapshots of local disks residing on [dedicated hosts](dedicated-host.md), use [Yandex Cloud Backup](../../backup/index.md). This service supports Ubuntu, CentOS, CentOS Stream, and Windows Server.

You cannot recover a boot disk of an existing VM from a snapshot or image. However, you can create a new VM to recover a boot disk from a snapshot. To recover the boot disk of an existing VM, use [Yandex Cloud Backup](../../backup/index.md).

## Disk snapshot as a Yandex Cloud resource {#snapshot-as-resource}

A disk snapshot is a resource, just like a disk itself. Snapshots are stored in a folder. Snapshot access permissions are inherited from folder access permissions.

A snapshot takes some space in the storage and is kept for an indefinite period of time. Snapshot storage is charged separately. To avoid unnecessary costs, delete unused snapshots. For more information, see [Compute Cloud pricing policy](../pricing.md).

Snapshot information contains the ID of the disk from which the snapshot was created. The license IDs (`product_ids`) used to calculate the disk usage cost are also inherited from the source.


## Reliable and secure snapshot storage {#reliability-and-security}

Snapshots are stored in Yandex Managed Service for YDB, replicated in multiple availability zones, and encrypted at the database level.

The checksum is stored for blocks in the snapshot. This checksum is checked when creating a disk from a snapshot.

To test disk recovery from a snapshot, [create a VM with a snapshot disk](../operations/vm-create/create-from-snapshots.md) and check the integrity of your data.


## Encrypting snapshots {#encryption}

To protect critical data in Compute Cloud, we recommend encrypting snapshots with [Yandex Key Management Service](../../kms/index.md) keys.

For more information, see [Encryption in Compute Cloud](encryption.md).

## Use cases {#examples}

* [High-performance computing (HPC) on preemptible VMs](../tutorials/hpc-on-preemptible.md)
* [Creating test VMs with GitLab CI](../../tutorials/testing/ci-for-snapshots.md)
* [Creating a 1C-Bitrix website](../../tutorials/web/bitrix-website/index.md)

#### Useful links {#see-also}

* [Guides on disk snapshots and schedules](../operations/index.md#snapshots)
* [Recovering a disk from a snapshot](../operations/disk-create/from-snapshot.md)
* [Disks, snapshots, and images](../qa/disks.md)