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:
utf8mb4_ai_ci character set. Tables created in NDB 8.0 by default use the
utf8mb4_ai_cicharacter 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_ciso that they use a character set supported in the older version prior to performing the backup.
Table metadata format. 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 cannot be restored using ndb_restore to NDB 7.6 or an earlier version of NDB Cluster. Such tables use
.sdifiles which are not understood by older versions of mysqld.
A backup taken in NDB 8.0 of tables which were created in NDB 7.6 or earlier, and which have not been altered since upgrading to NDB 8.0, should be restorable to older versions of NDB Cluster.
Since it is possible to restore metadata and table data separately, you can in such cases restore the table schemas from a dump made using mysqldump, or by executing the necessary
CREATE TABLEstatements manually, then import only the table data using ndb_restore with the
Multi-threaded backups. Multi-threaded backups taken in NDB 8.0 can be restored to an cluster running an earlier version of
NDBin either of the following two ways:
Using an ndb_restore binary from NDB 8.0, perform a parallel restore. See Section 18.104.22.168, “Restoring a parallel backup in parallel”.
Restore the backups serially; in this case, a later version of ndb_restore is not required. See Section 22.214.171.124, “Restoring a parallel backup serially”.
Encrypted backups. Encrypted backups created in NDB 8.0.22 and later cannot be restored using ndb_restore from NDB 8.0.21 or earlier.
NDB_STORED_USER privilege. The
NDB_STORED_USERprivilege is supported only in NDB 8.0.
Maximum number of data nodes. NDB Cluster 8.0 supports up to 144 data nodes, while earlier versions support a maximum of only 48 data nodes. See Section 126.96.36.199, “Restoring to Fewer Nodes Than the Original”, for information with situations in which this incompatibility causes an issue.