Netbackup Communication Buffer configuration - NET_BUFFER_SZ

Thanks. I will check the documentation provided.

 http://seer.entsupport.symantec.com/docs/244652.htm

thanks Taqadus,
I actually set the communication buffer to 256K on Windows, the NET_BUFFER_SZ to 262144 on Linux. and on both media and master NUMBER_DATA_BUFFERS 64 and SIZE_DATA_BUFFERS 65536
there's a huge improvements on unix but on Windows it is is slow, like 6 or 7 Mbps as a throughput.
on Linux it is between 15 and 30 Mbps.

All the LAN s Gigabit Ethernet, and the tape library is ML6020 LTO3/ Master and Media servers on Win 2k3 SP2 Netbackup 6MP6.

Any additional settings on the client/server/media server can be done to increase the backup speed?

thanks for your input

• Please tell me what is the actual size of (windows) backup?
• Is this backup contain many small files? if yes then Run the following bpbkar throughput test on the client with Windows:

• Do you please check TCP/IP throughput?

• Disk I/O can also effect the backup throughput do check that as well. 

 

Hi

The actual size varies from one server to a server; it is around 20GB (a couple goes up to 50) for more than 20 servers.
I have tried the the command, it retuns a blank line.
Network utilization on the backp interface is quite normal.10 to 20 % during the backup in 1 GB Network interface
Disk read is max reaching 16400000Bytes / sec.
Yes some servers have a lot of small files to backup.

Once some servers, I have increasing hte communication buffer to 512KB, I had an improvement in the performance, not what expected.



Thanks Again Taqadus.

Hi Robert,

You need to create the bpbkar log directory on the Widnows client to do the test Taqadus told you.

C:\Program Files\VERITAS\NetBackup\logs\bpbkar

After you run the bpbkar32 -nocont test on the Windows client (wait for a while even thouth it seems doing nothing), go to the bpbkar log directory and you whoudl see a log created, such as 040909.log.  Open it with WordPad (or make a copy and open it if it says the file is accessed by another application), and you should see something like this:

12:00:22.810 PM: [7580.7588] <2> tar_base::backup_finish: TAR - backup:       elapsed time:        654 secs    127416036 bps

which tells you how fast NetBackup client (bpbkar process) can read on that local Windoows machine.  In the case above is 127416036 byte/sec = 121 MB/sec.  I can never run backup that fast from this Windows machine, so as the Symantec document (see below) suggested, you should run at least 3 times on the dataset with > 10 GB size to get a clear figure.

(DOCUMENTATION: How to benchmark the performance of the bpbkar32 process on a Windows client )
http://seer.entsupport.symantec.com/docs/242918.htm

 Netbackup take longer to backup multiple small files of the same total size as a single large file. what you can do is

- use FlashBackup (or Flashbackup-Window) policy type. this is feature of netbackup advance client (if you have advance clients).

- Make sure  Netbackup process are free from Viruse Scan. this may double performance.

- Make sure the NetBackup buffer size is the same size on both the servers 
and clients.

- Turn off NetBackup Client Job Tracker if the client is a system server.. 

- Regularly review the patch announcements for every server OS. Install patches that affect TCP/IP functions, such as correcting out-of-sequence delivery of packets.