Does NetBackup limit throughput?
Hey eveyone,
I was woundering if anyone knew if netbackup limited throughput to a media server. We have two media servers in our of our datacenters and we have noticed that both servers get maxed out at 60 megabytes a second of throughoput for each. This has caused issues when trying to run backups.
We think it might be a Network issue but I want to make sure there is no setting somewhere in the NetBackup application that is limiting bandwidth.
There are various methods for testing performance capabilities.
There's 1 method that basically reads the client file system and backs it up to the null device. For Windows clients, see http://www.symantec.com/business/support/index?page=content&id=TECH17541. There's a similar one for Unix clients. This will tell you how fast the client can read the data. You can obviously never back up faster than the client can read the file system data.
Method 2 takes it from the client and creates an image on the media server. This gives you a repeatable data stream. See http://www.symantec.com/business/support/index?page=content&id=TECH75213.
Third, there are many methods of testing the network bandwidth between 2 servers. I've used iperf in the past and it worked for me. http://iperf.sourceforge.net/.
Fourth, don't forget about what the media server is doing with the data. If you're writing to a disk unit, your backup speed will be limited by your write rate. If you're doing simultaneous read/writes to the same file system on the media server, that will impact your client backup speed.
Last, don't expect 100+ MB/sec from a 1GigE network. A typical rule of thumb is 70% of the capacity of any device - whether it's cpu, memory, or disk (tape is a rare exception). If you're getting 60MB/sec from a single GigE network without using jumbo frames, you're not far off from the maximum you can expect to get. If you've got a 10GigE network in place, then you can obviously go a lot faster.
