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Backup your Data

docs/operating-scylla/procedures/backup-restore/backup.rst

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================ Backup your Data

Even though ScyllaDB is a fault-tolerant system, it is recommended to regularly back up the data to external storage.

  • Backup is a per-node procedure. Make sure to back up each node in your cluster. For cluster-wide backup and restore, see ScyllaDB Manager <https://manager.docs.scylladb.com/stable/restore/>_.
  • Backup works the same for non-encrypted and encrypted SStables. You can use :doc:Encryption at Rest </operating-scylla/security/encryption-at-rest> without affecting the backup procedure.

You can choose one of the following:

  • :ref:Full Backup <backup-full-backup-snapshots> - Copy the entire data of a node.

  • :ref:Incremental Backup <backup-incremental-backup> - Updates (delta) - flushed SSTables.

.. _backup-full-backup-snapshots:

Full Backup - Snapshots

Snapshots are taken using :doc:nodetool snapshot </operating-scylla/nodetool-commands/snapshot>. First, the command flushes the MemTables from memory to SSTables on disk, and afterward, it creates a hard link for each SSTable in each keyspace. With time, SSTables are compacted, but the hard link keeps a copy of each file. This takes up an increasing amount of disk space. It is important to clear space by :doc:clean unnecessary snapshots </operating-scylla/procedures/backup-restore/delete-snapshot>.

Procedure

| 1. Data can only be restored from a snapshot of the table schema, where data exists in a backup. Backup your schema, roles, permissions | and service levels with the following command:

| $: cqlsh -e "DESC SCHEMA WITH INTERNALS AND PASSWORDS" > <schema_name.cql>

| For example:

| $: cqlsh -e "DESC SCHEMA WITH INTERNALS AND PASSWORDS" > db_schema.cql

| The command can only be executed by a superuser.

.. warning::

To get a proper schema description, you need to use cqlsh at least in version 6.0.23. Restoring a schema backup created by an older version of cqlsh may lead to data resurrection or data loss. To check the version of your cqlsh, you can use cqlsh --version.

See :doc:the relevant article to learn more </cql/describe-schema>.

| | 2. Take a snapshot, including every keyspace you want to backup.

| $ nodetool snapshot <KEYSPACE_NAME>

| For example:

| $ nodetool snapshot mykeyspace

| The snapshot is created under ScyllaDB data directory /var/lib/scylla/data | It will have the following structure: | keyspace_name/table_name-UUID/snapshots/snapshot_name

| For example: | /mykeyspace/team_roster-91cd2060f99d11e6a47a000000000000/snapshots/1487847672222

From one of the nodes, recreate the schema. Repeat these steps for each node in the cluster.

.. _backup-incremental-backup:

Incremental Backup

| Enabling the incremental backup (disabled by default) will create a hard-link from each SSTable, right after it is flushed, to a backups directory. | For a complete point in time backup, the following is required:

  • A snapshot
  • All incremental backups and commit logs from the time of the snapshot.
  • Make sure to delete unnecessary incremental backups. ScyllaDB does not do this automatically.

Procedure

| 1. In the /etc/scylla/scylla.yaml file set the incremental backups parameters to true and restart the ScyllaDB service. Snapshot are created under ScyllaDB data directory /var/lib/scylla/data | with the following structure: | keyspace_name/table_name-UUID/backups/backups_name

| For example: | /mykeyspace/team_roster-91cd2060f99d11e6a47a000000000000/backups/1437827672721

Additional Resources

  • :doc:ScyllaDB Snapshots </kb/snapshots>