Oracle 5.0 Reference Manual page 1601

The default value for this parameter should be sufficient for most applications. In fact, it is more likely
for a backup failure to be caused by insufficient disk write speed than it is for the backup log buffer
to become full. If the disk subsystem is not configured for the write load caused by applications, the
cluster is unlikely to be able to perform the desired operations.
It is preferable to configure cluster nodes in such a manner that the processor becomes the
bottleneck rather than the disks or the network connections.
The default value is 2MB.
•
BackupMemory
Effective Version
MySQL 5.0.0
Restart Type: N
This parameter is simply the sum of
The default value is 2MB + 2MB = 4MB.
Important
If
exceed 4MB, then this parameter must be set explicitly in the
file to their sum.
•
BackupWriteSize
Effective Version
MySQL 5.0.0
Restart Type: N
This parameter specifies the default size of messages written to disk by the backup log and backup
data buffers.
The default value is 32KB.
•
BackupMaxWriteSize
Effective Version
MySQL 5.0.0
Restart Type: N
This parameter specifies the maximum size of messages written to disk by the backup log and
backup data buffers.
The default value is 256KB.
Important
When specifying these parameters, the following relationships must hold true.
Otherwise, the data node will be unable to start.
•
BackupDataBufferSize >= BackupWriteSize + 188KB
MySQL Cluster Configuration Files
Type/Units
bytes
BackupDataBufferSize
BackupDataBufferSize
Type/Units
bytes
Type/Units
bytes
1581
Default
4M
and BackupLogBufferSize.
and
BackupLogBufferSize
Default
32K
Default
256K
Range/Values
0 - 4G
taken together
config.ini
Range/Values
2K - 4G
Range/Values
2K - 4G