NetBackup and Windows TCPIP

[rizwan84tx]

Dear all,

I would like to increase the tcpip window size on our media server from 64k (default) to 128k. Server NBU buffer size in 32. After increasing the TCPIP window size do i need to change the buffer size of media server to 128 too?

Master/Media Server - NBU 6.5.6 (combo)

OS: Windows 2003 x64 EE

[Marianne]

Extract from Planning and Performance Guide  http://www.symantec.com/docs/TECH62317 :

Network buffer size in relation to other parameters
The network buffer size parameter is the counterpart on the media server to the
communications buffer size parameter on the client. The network buffer sizes
need not be the same on all of your NetBackup systems for NetBackup to function
properly. However, if the media server’s network buffer size is the same as the
client’s communications buffer size, network throughput may improve.

Similarly, the network buffer size does not have a direct relationship to the
NetBackup data buffer size.

The two buffers are separately tunable parameters. However, setting the network
buffer size to a substantially larger value than the data buffer has achieved the
best performance in many NetBackup installations.

[rizwan84tx]

Thanks Marianne, I will go ahead and change the TCP network buffer at 128 and NetBackup communication buffer at 64. Let me see how the performance is and update you all.

Please advice whether the above implementation is good!!!

[Marianne]

There is no exact science when it comes to tuning - no 'one size fits all' .

Performance Tuning is an ongoing exercise - carefully monitor performance after each change.

Let us know what works for you!

[rizwan84tx]

Sure i will. On observing the number and size of data buffers

NUMBER_DATA_BUFFERS = 256
SIZE_DATA_BUFFERS = 262144
TOT DRIVES = 4
MULTIPLEX SETTING= 32

The ideal amount of Shared memory required must be 8589934592

(number_data_buffers * size_data_buffers) *
number_tape_drives * max_multiplexing_setting

But, BPTM logs show shared memory size used as 67115016

00:28:04.624 [9540.5144] <2> io_init: using 262144 data buffer size
00:28:04.624 [9540.5144] <2> io_init: CINDEX 0, sched Kbytes for monitoring = 60000
00:28:04.624 [9540.5144] <2> io_set_recvbuf: setting receive network buffer to 1049600 bytes
00:28:04.624 [9540.5144] <2> io_init: using 256 data buffers
00:28:04.624 [9540.5144] <2> io_init: child delay = 10, parent delay = 15 (milliseconds)
00:28:04.624 [9540.5144] <2> create_shared_memory: shm_size = 67115016, buffer address = 0x1e80000, buf control = 0x5e80000, ready ptr = 0x5e81800

Any Idea on the difference between these figures?

[rizwan84tx]

The Media server  does not have  NET_BUFFER_SZ file, but the BPTM output is weired, it shows 1049600 bytes as receive buffer. Please advice if this is normal or i'm looking into wrong place in the log.

18:08:05.177 [6160.8528] <2> io_set_recvbuf: setting receive network buffer to 1049600 bytes

18:08:05.177 [6160.8528] <2> io_set_recvbuf: receive network buffer is 1049600 bytes

For window media server, default network buffer size is 256k, how can it receive buffer at 1024 kb; Is my Operating System  influencing this ?

[rizwan84tx]

Any Update please?

[Anton_Panyushki]

I presume you have read this http://www.symantec.com/docs/TECH1724

Is is the essential technote for NetBackup Buffers tuning.

It is true, there are no NET_BUFFER_SZ on a media by default, you hacve to create it manually.

[Anton_Panyushki]

I presume you have read this http://www.symantec.com/docs/TECH1724

That is the essential technote for NetBackup Buffers tuning.

It is true, there are no NET_BUFFER_SZ on a media by default, you hacve to create it manually.

[Marianne · Accepted solution]

The defaults are listed in the Performance Tuning Guide (link in my post above).

Extract:

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. This buffer either receives data from the network
(a backup) or writes data to the network (a restore). The parameter sets the value
for the network buffer size for backups and restores.
UNIX
The default value for this parameter is 32032.
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.

[rizwan84tx]

"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."

----- We are backing up the data to LTO4 tapes, so as per the book default network buffer must be 263168
bytes.

As per the formula which Marrianne refered , i noticed we have set SIZE_DATA_BUFFER as 262144 bytes. Now that clears the question.

Any idea , where will be the Shared memory will be stored? and is there any limitation for amount of shared memory required?