BRBACKUP to Tape - write performance
I am seeking to improve write to LT04 performance. As it stands today the backups are working fine with a reasonable write speed, but as our databases are growing its taking longer and longer for the backups to finish.
In the below example, I'll attempt to explain the design..
We have a ~ 300GB database which takes around 1 hr to backup to fiber connected ULTRIUM TLD4 tape drives. The backup is run by backint (brbackup) from the media server.
Below are the current parameters we use..
DRIVES = 16 (in initSID.utl file which means 16 streams)
MPX = 4 (in the NBU Policy which means 4 streams per tape/drive)
NET_BUFFER_SZ = 262144
NUMBER_DATA_BUFFERS = 12
SIZE_DATA_BUFFERS = 65536
Fragment size on the LT04 drive = 1048575
I have tried to tweak some of the above paramters like N_D_B to 16 and S_D_B to 1048575, also tried to increase the number of streams per drive and tried to throw more drives at the backup by decreasing the MPX, but nothing seems to be making any difference in the overall backup time. Although I have seen 3 out of 16 streams goes much faster if I tweak the parameters but it don't matter because the time is determined by the slowest stream.
I am looking for ideas from the experts here, I ultimately have to apply this solution to a 3TB (ever growing) database which takes around 8 hours to backup to tape. Please let me know if you need anymore information.
Appreciate your response in advance..