MySQL 5.7 Reference Manual
MySQL 5.7 Release Notes
This section provides information about compatibility between different NDB Cluster 7.6 releases with regard to performing upgrades and downgrades as well as compatibility matrices and notes. Additional information can also be found here regarding downgrades from NDB 7.6 to previous NDB release series. You should already be familiar with installation and configuration of NDB Cluster prior to attempting an upgrade or downgrade. See Chapter 4, Configuration of NDB Cluster.
The table shown here provides information on NDB Cluster upgrade and downgrade compatibility among different releases of NDB 7.6. Additional notes about upgrades and downgrades to, from, or within the NDB Cluster 7.6 release series can be found following the table.
Version support. The following versions of NDB Cluster are supported for upgrades to GA releases of NDB Cluster 7.6 (7.6.6 and later):
NDB Cluster 7.5 GA releases (7.5.4 and later)
NDB Cluster 7.4 GA releases (7.4.4 and later)
NDB Cluster 7.3 GA releases (7.3.2 and later)
Known Issues When Upgrading or Downgrading NDB Cluster 7.6. The following issues are known to occur when upgrading to, downgrading from, or between NDB 7.6 releases:
Changes in Disk Data file format. Due to changes in disk format, upgrading to or downgrading from either of the versions listed here requires an initial node restart of each data node:
NDB 7.6.2
NDB 7.6.4
To avoid problems relating to the old format, you should
re-create any existing tablespaces and undo log file groups when
upgrading. You can do this by performing an initial restart of
each data node (that is, using the
--initial option) as part of the
upgrade process.
If you are using Disk Data tables, a downgrade from
any NDB 7.6 release to any NDB 7.5 or
earlier release requires that you restart all data nodes with
--initial as part of the downgrade
process. This is because NDB 7.5 and earlier release series are
not able to read the new Disk Data file format.
IndexMemory changes.
If you are downgrading from NDB 7.6 to NDB 7.5 (or earlier),
you must set an explicit value for
IndexMemory in the
cluster configuration file if none is already present. This is
because NDB 7.6 does not use this parameter and sets it to 0
by default, whereas it is required in NDB 7.5 and earlier
releases, in which the cluster refuses to start with
Invalid configuration received from Management
Server... if IndexMemory is not
set to a nonzero value.
Important
Upgrading to NDB 7.6 from an earlier release, or downgrading
from NDB 7.6 to an earlier release, requires purging then
re-creating the NDB data node file system,
which means that each data node must be restarted using the
--initial option as part of the
rolling restart or system restart normally required. (Starting
a data node with no file system is already equivalent to an
initial restart; in such cases, --initial is
implied and not required. This is unchanged from previous
releases of NDB Cluster.)
When such a restart is performed as part of an upgrade to NDB
7.6, any existing LCP files are checked for the presence of
the LCP Sysfile, indicating that the
existing data node file system was written using NDB 7.6. If
such a node file system exists, but does not contain the
Sysfile, and if any data nodes are
restarted without the --initial
option, NDB causes the restart to fail with
an appropriate error message.
You should also be aware that no such protection is possible when downgrading from NDB 7.6 to a release previous to NDB 7.6.