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The -c  option is used to specify a connection string which tells ndb_restore  where to locate the cluster management server (see Section 23.3.3.3, “NDB Cluster Connection Strings” ). If this option is not used, then ndb_restore  attempts to connect to a management server on localhost:1186 . This utility acts as a cluster API node, and so requires a free connection “slot”  to connect to the cluster management server. This means that there must be at least one [api]  or [mysqld]  section that can be used by it in the cluster config.ini  file. It is a good idea to keep at least one empty [api]  or [mysqld]  section in config.ini  that is not being used for a MySQL server or other application for this reason (see Section 23.3.3.7, “Defining SQL and Other API Nodes in an NDB Cluster” ). 

In NDB 8.0.22 and later, ndb_restore  can decrypt an encrypted backup using --decrypt  and -- backup-password . Both options must be specified to perform decryption. See the documentation for the START BACKUP  management client command for information on creating encrypted backups. 

You can verify that ndb_restore  is connected to the cluster by using the SHOW  command in the ndb_mgm management client. You can also accomplish this from a system shell, as shown here: 

shell> ndb_mgm -e "SHOW" 

## Error reporting. 

ndb_restore  reports both temporary and permanent errors. In the case of temporary errors, it may able to recover from them, and reports Restore successful, but encountered temporary error, please look at configuration  in such cases. 

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## Important 

After using ndb_restore  to initialize an NDB Cluster for use in circular replication, binary logs on the SQL node acting as the replica are not automatically created, and you must cause them to be created manually. To cause the binary logs to be created, issue a SHOW TABLES  statement on that SQL node before running START SLAVE . This is a known issue in NDB Cluster. 

## 23.4.23.1 Restoring an NDB Backup to a Different Version of NDB Cluster 

The following two sections provide information about restoring a native NDB backup to a different version of NDB Cluster from the version in which the backup was taken. 

In addition, you should consult Section 23.2.7, “Upgrading and Downgrading NDB Cluster” , for other issues you may encounter when attempting to restore an NDB backup to a cluster running a different version of the NDB software. 

It is also advisable to review What is New in NDB Cluster 8.0, as well as Section 2.11.4, “Changes in MySQL 8.0” , for other changes between NDB 8.0 and previous versions of NDB Cluster that may be relevant to your particular circumstances. 

## Restoring an NDB backup to a previous version of NDB Cluster 

You may encounter issues when restoring a backup taken from a later version of NDB Cluster to a previous one, due to the use of features which do not exist in the earlier version. Some of these issues are listed here: 

•Tables created in NDB 8.0 by default use the utf8mb4_ai_ci  character set, which is not available in NDB 7.6 and earlier, and so cannot be read by an ndb_restore  binary from one of these earlier versions. In such cases, it is necessary to alter any tables using utf8mb4_ai_ci  so that they use a character set supported in the older version prior to performing the backup. 

•Due to changes in how the MySQL Server and NDB handle table metadata, tables created or altered using the included MySQL server binary from NDB 8.0.14 or later cannot be restored using 

