[Veritas-bu] NET_BUFFER_SZ vs communications buffer size

Sorry Bob, got a little lost in what you're asking.

SIZE_DATA_BUFFERS is the size of the blocks that netbackup buffers
before writing to tape, which, as I understand it, should correlate with
the block size of the tape drive devices you're using....***to get the
best performance***.

In other words, if your tape drives use 256k blocks, and you configure
netbackup to send 196k blocks to the drives, then you're not gonna get
the best performance from your drives.

NET_BUFFER_SIZE, as I understand it, is the server side part of the
"communications buffer" on the client....which is the size of the block
the client buffers before sending the block to the server.

Again, if all nodes have the same value, you will make the most
efficient use of the buffers.
If your clients are set to 16k and the server set to 64k, then there's
additional work being done to stuff 4 client blocks into 1 server block.
If clients and servers are set to 64k, then you go 1 to 1, and move on,
and is therefore more efficient.

This is my understanding of it....

Paul

> -----Original Message-----
> From: veritas-bu-admin AT mailman.eng.auburn DOT edu 
> [mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu] On Behalf Of 
> Bob Stump
> Sent: January 5, 2006 9:14 AM
> To: veritas-bu AT mailman.eng.auburn DOT edu
> Subject: [Veritas-bu] NET_BUFFER_SZ vs communications buffer size
> 
> 
> Will someone please explain the differences between the  
> $INSTALL_DIR\NetBackup\NET_BUFFER_SZ and the "communications 
> buffer" in the properties window. 
> Why are the suggested settings for window's "communication 
> buffer" = 129 and the NET_BUFFER_SZ = value used for 
> SIZE_DATA_BUFFERS (which I have set to 262144 for 9940 tape 
> drives). Also I have seen conflicting use in technotes for 
> NET_BUFFER_SZ. One technote says all MASTER/MEDIA/CLIENTS 
> must have the same value. In other words if you set it up 
> once then you must set it up on ALL/EVERYWHERE. I have also 
> seen a technote that says to use it on MASTER/MEDIA servers 
> with no reference to also ensure it is being used on ALL clients.
> 
> 
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