Windows 2008 R2, Netbackup 7.1, NET_BUFFER_SZ
I am seeing 'unexpected' results when setting the NET_BUFFER_SZ and Communications buffers on the Windows platform with NBU 7.1 (update 7101) and Windows 2008R2.
Whatever I set the values to, the job log reports that it is using 262144 data buffer size and the the receive network buffer size is being set to 1049600. I have varied the values in the communications buffer on te client from 16, 32, 64, 129, 256 - and the NET_BUFFER_SZ on the media server to the corresponding values.
Are these values recognised in 7.1 ?
My issue is that I have seen a significant decrease in throughput from the network clients since a move of hardware and implemented the server touchfiles NET_BUFFER_SZ. Previously the site had got all clients set to 129 communications buffer, but had the NET_BUFFER_SZ touchfile in the wrong location. I have now created it in the correct location (install_directory\netbackup) but the values appear to be being ignored.
Any help appreciated.
AJ.
Check page 116 on this guide. NET_BUFFER_SZ is a parameter for media server, and must be specified by bytes. Value of 256(or less) is too small. Your current value must be brought by a value of SIZE_DATA_BUFFERS(256kb x 4 + 1024).
http://www.symantec.com/docs/DOC4483
Setting the network buffer size for the NetBackup media server
The NetBackup media server has a tunable parameter that you can use to adjust
the size of the network buffer space. The operating system uses this buffer space
for the connection between the bptm child process and the client process. This
buffer space caches either received data from the network (a backup) or written
data to the network (a restore). The parameter sets the value for NetBackup to
use for the network buffer space, but the operating system may not allow the
change.
:
Windows
The default value for this parameter is derived from the NetBackup data buffer
size using the following formula:
For backup jobs: (<data_buffer_size> * 4) + 1024
For restore jobs: (<data_buffer_size> * 2) + 1024
For tape:
Because the default value for the NetBackup data buffer size is 65536 bytes, the
formula results in the following: a default NetBackup network buffer size of 263168
bytes for backups and 132096 bytes for restores.
For disk:
Because the default value for the NetBackup data buffer size is 262144 bytes, the
formula results in the following: a default NetBackup network buffer size of
1049600 bytes for backups and 525312 bytes for restores.
Tuning the NetBackup data transfer path 117
NetBackup network performance in the data transfer path
To set the network buffer size
1 Create the following files:
UNIX
/usr/openv/netbackup/NET_BUFFER_SZ
/usr/openv/netbackup/NET_BUFFER_SZ_REST
Windows
install_path\NetBackup\NET_BUFFER_SZ
install_path\NetBackup\NET_BUFFER_SZ_RESTYour performance degration may be caused by "a move of hardware" itself (change of bandwidth or latency, incorrect setting of NIC negotiation, ...).
