I am using netbackup 5.1 with rman for my oracle database backups.OS is
Solaris 9 with oracle 9.2.0.7 and I am unable to get a speed more than
50MB/sec. For FS backup this speed is 100MB/sec but for rman I get
stucked at 50MB/sec. I don't know why I am unable to get more speed.

The library is L100 and I am using two drives for backup. By increasing
number of drives or number of channels the backup speed is not going to
be better.


The tunning I have made so far is.


NET_BUFFER_SZ as 262144
NUMBER_DATA_BUFFERS=64
SIZE_DATA_BUFFERS=1048576


The rman backup script is like this.


CMD_STR="
ORACLE_HOME=$ORACLE_HOME
export ORACLE_HOME
ORACLE_SID=$ORACLE_SID
export ORACLE_SID
$RMAN target $TARGET_CONNECT_STR catalog rman/rman at rman trace
/u09/rman.trc msglog $RMAN_LOG_FILE append << EOF
RUN {
debug io;
ALLOCATE CHANNEL ch01 TYPE 'SBT_TAPE' PARMS  'BLKSIZE=1048576'
MAXOPENFILES=20;
ALLOCATE CHANNEL ch02 TYPE 'SBT_TAPE' PARMS  'BLKSIZE=1048576'
MAXOPENFILES=20;
SEND 'NB_ORA_SERV=bserver-bk,NB_ORA_CLIENT=client3-bk';
BACKUP
    $BACKUP_TYPE
    FILESPERSET 20
    # recommended format
    FORMAT 'bk_%s_%p_%t'
    DATABASE;
    sql 'alter system archive log current';
RELEASE CHANNEL ch01;
RELEASE CHANNEL ch02;
# backup all archive logs
ALLOCATE CHANNEL ch01 TYPE 'SBT_TAPE' PARMS  'BLKSIZE=1048576';
ALLOCATE CHANNEL ch02 TYPE 'SBT_TAPE' PARMS  'BLKSIZE=1048576';
SEND 'NB_ORA_SERV=bserver-bk,NB_ORA_CLIENT=client3-bk';
BACKUP
   filesperset 20
   FORMAT 'al_%s_%p_%t'
   ARCHIVELOG ALL DELETE INPUT;
RELEASE CHANNEL ch01;
RELEASE CHANNEL ch02;


Any idea will be highly appreciated.


thanks,
atif