What buffers need to be changed and what values should be used for DataCentre?

Newsgroups etc have been confusing the issue with buffers and their right syntax etc - Here is some information as to what the buffer settings are about and the correct spelling, CASE etc...

The data is read from the disk and buffered before it enters the network. This is the Communications buffer or registry key 'Buffer_Size'. The media server buffers the data coming off the network from the client. This is the network receive buffer or NET_BUFFER_SZ. Then, the media server buffers the data before sending it to tape. This is the tape buffer or SIZE_DATA_BUFFERS and NUMBER_DATA_BUFFERS.

To change the communications buffer - Bring up the properties for the client and browse to the "Windows Client" tab. If you are running any flavour of Windows - Change the "Communications Buffer Size" to 129.

The network receive buffer a.k.a. Communications Buffer
<install_path>\netbackup\NET_BUFFER_SZ
Add the desired value in this file, expressed in bytes, in multiples of 1024. Ensure the file has no extensions after saving. This setting can be larger than 65536 and may need to be tweaked to get the best performance. We have found that the ideal setting is 132096. Ideally, the network receive buffer (NET_BUFFER_SZ) and the data buffer (SIZE_DATA_BUFFERS) should be the same.

The tape buffer
<install_path>\netbackup\db\config\SIZE_DATA_BUFFERS
Add the desired value in this file, expressed in bytes, in multiples of 1024. Ensure the file has no extensions after saving. From our testing we have found that for DLT drives the ideal setting is 65536 and for LTO drives 262144. If you select a value higher than what the tape drive can handle, in the bptm logs you will see:
[color red]08:48:51.426 [724.1248] <16> io_open: The tape device at index -1 has a maximum block size of 65536 bytes, a buffer size of 132096 cannot be used[/color]

The number of tape (data) buffers
<install_path\netbackup\db\config\NUMBER_DATA_BUFFERS
The default setting for this is 16 data buffers

To see how your system is doing, check the bptm log files for the following lines:

[color red]13:10:26 [1996.2392] <2> write_data: waited for full buffer 2341 times, delayed 3362 times[/color]
+ BPTM is waiting for data from the source so data is not arriving fast enough (Each delay is 30ms)
+ Add Multiplexing
[color red]00:53:05 [25928] <2> fill_buffer: [48992] socket is closed, waited for empty buffer 23992 times, delayed 24145 times, read 11040576 Kbytes [/color]
+ BPTM is waiting for an empty buffer so data is arriving faster than it can be written.
+ Increase the NUMBER_DATA_BUFFERS.
+ Reduce multiplexing.