The various number data buffers files must contain a single integer that specifies the number of shared data buffers NetBackup uses.

If the NUMBER_DATA_BUFFERS file exists, its contents determine the number of shared data buffers to be used for multiplexed and non-multiplexed backups.

The values specified in these files override either the NetBackup default number or the value that is specified in NUMBER_DATA_BUFFERS.

For example, NUMBER_DATA_BUFFERS_DISK allows for a different value when you back up to disk instead of tape. If NUMBER_DATA_BUFFERS exists but NUMBER_DATA_BUFFERS_DISK does not, NUMBER_DATA_BUFFERS applies to tape and disk backups. If both files exist, NUMBER_DATA_BUFFERS applies to tape backups and NUMBER_DATA_BUFFERS_DISK applies to disk backups. If only NUMBER_DATA_BUFFERS_DISK is present, it applies to disk backups only.

The NUMBER_DATA_BUFFERS file also applies to remote NDMP backups, but does not apply to local NDMP backups or to NDMP three-way backups.

The NUMBER_DATA_BUFFERS_RESTORE file is only used for restore from tape, not from disk. If the NUMBER_DATA_BUFFERS_RESTORE file exists, its contents determine the number of shared data buffers for multiplexed restores from tape.

The NetBackup daemons do not have to be restarted for the new buffer values to be used. Each time a new job starts, bptm checks the configuration file and adjusts its behavior.

For a recommendation for setting NUMBER_DATA_BUFFERS_FT, refer to the following topic: