number of data buffers and size for LTO6 drives

[yilkilicaslan]

What is the best numbers of number of data buffers and size for LTO6 drives? And which paramaters do i have to tune for best performance?

[Yogesh9881]

"number of data buffers and size for LTO6 drives"  -- totally depends on what OS on master / media  server ?

http://www.symantec.com/docs/HOWTO56144

http://www.symantec.com/docs/HOWTO56079

https://www-secure.symantec.com/connect/forums/how-data-buffer-size-and-buffer-number-effect-netback...

[mph999 · Accepted solution]

Try

    echo "262144" > /usr/openv/netbackup/db/config/SIZE_DATA_BUFFERS

    echo "64"     > /usr/openv/netbackup/db/config/NUMBER_DATA_BUFFERS

... to start with

Then increase NUMBER to 128, test again, then try 256.

Remeber to test backup and restore.  Settings go on media server, no restart required.

Martin

[yilkilicaslan]

Master is Windows Server 2008 R2

Media servers are Netbackup 5220 Appliances.

[Marianne]

See Symantec NetBackup 52xx Appliance Administrator's Guide: DOC6345

Setting data buffer parameters on p. 72.

We see on p. 73 that the default Buffer size is already 262144.

Default number of data buffers is 30.

Best to check bptm log for effect of existing buffers before you change anything. 

Any change should always be documented and effects double-checked in bptm log.

Look for '... waited for full/empty buffers... ' at the end of each backup and/or duplication.

[Steve_Lussiaud]

Hello,

just for your information but increase these values consume more shared memory on your server.

Think to check / tune shared memory availability too.