Restore tables | ScyllaDB Docs

Restore tables¶

Note

Currently, Scylla Manager does not support restoring content of CDC log tables.

Warning

Restoring data related to authentication (system_auth) and service levels (system_distributed.service_levels) is not supported in ScyllaDB 6.0.

To restore the content of the tables (rows), use the sctool restore command with the --restore-tables flag.

The restore tables procedure works with any cluster topologies, so the backed-up cluster can have a different number of nodes or data centers than the restore destination cluster.

You can add the --keyspace flag to define the base tables that will be restored. All Materialized Views and Secondary Indexes of those tables will be automatically recreated in order to ensure the correct data state.

Prerequisites¶

Scylla Manager requires CQL credentials with:
- permission to alter restored tables.
- permission to drop and create Materialized Views and Secondary Indexes of restored tables.
Restoring the content of the tables assumes that the correct schema (identical as in the backup) is already present in the destination cluster.

Scylla Manager does NOT validate that, so it’s user responsibility to ensure it. The only form of validation that Scylla Manager performs is checking whether restored tables are present in destination cluster, but it does not validate their columns types nor other properties. In case destination cluster is missing correct schema, it should be restored first.

Note that this requirement also applies to the keyspace schema. Keyspace (where restored tables live) should have the correct schema, including the replication strategy. It can be changed after successful restore according to: How to Safely Increase the Replication Factor.
It is strongly advised to restore the contents of the tables only into truncated tables.

Otherwise, restored tables’ contents might be overwritten by the already existing ones. Note that an empty table is not necessarily truncated!
All nodes in restore destination cluster should be in the UN state (See nodetool status for details).

Procedure¶

This section contains a description of the restore-tables procedure performed by ScyllaDB Manager.

For each backup location:

Find live Scylla nodes that will be used for restoring current location

Find nodes local to location

If non can be found, find any node with location access

List backup manifests for specified snapshot tag

Record restored views definitions and drop them

Record restored tables tombstone_gc mode and change it to tombstone_gc = {'mode': 'disabled'} (ensure restored data consistency)

For each manifest:

Filter relevant tables from the manifest

For each table:

Group SSTables to bundles by ID

Join bundles into batches containing batch size bundles each

For each batch (in --parallel):

Select node with enough free space to restore given batch

Download batch to node’s upload directory

Call load and stream with primary_replica_only

Repair restored tables

Reset all restored tables tombstone_gc to its original mode

Recreate restored views

Information about original tombstone_gc mode, views definitions and repair progress is included in sctool progress –details.

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