Increase speed in RMAN channel

[Zailar]

Hello,

In the RMAN we backup in 4 channel using infiny band. Channel 1 speed 120000 kb/sec, channel 2 speed 110000 kb/sec, channel 3 speed 115000 kb/sec and channel 4 speed 130000 kb/sec. If the channel 1, 2 and 3 finished backup, why the speed in channel 4 a little increase maybe just only 170000 kb/sec  not more?. Any parameter setting in netbackup or oracle?.

Thank you

Zainal

[Nicolai]

Hard to tell with information available - but I guess it's because infinity band is not the bottleneck.

[Marianne]

Channel 1 speed 120000 kb/sec = 120 Mb/sec
channel 2 speed 110000 kb/sec = 110 Mb/sec
channel 3 speed 115000 kb/sec = 115 Mb/sec
channel 4 speed 130000 kb/sec = 130 Mb/sec

All channels are basically backing up at maximum tape drive speed.

Channel 4 is your fastest backup! Maybe backup takes longer because it is backing up much more data?

You can read through NBU Planning and Performance Tuning Guide and Google for Rman Performance Tuning, but I seriously doubt that anything is going to improve your performance dramatically.

This is as good as it gets!!

[Zailar]

Thanks Marianne,

I was tunning NET_BUFFER_SZ = 268435456 and i will check the RMAN tuning.

[pmbgat]

Take a look at slide 24 of http://www.oracle.com/technetwork/database/features/availability/s316928-1-175928.pdf for some suggestions on RMAN tuning. Channel 4 running longer than the other channels may be due to the files that are selected to be placed in that channel. The physical configuration of the devices used by the database on the physical storage my have an impact on the throughput of the backup. Without additional configuration data it is hard to make suggestions on the location of your performance bottleneck.