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Backup running very slow in Netbackup 7.0.1

Level 6

Hello Experts,

We are using NBU 7.0.1 on win-2k8 R2 standard as Master/Media server which has attached TL-4000 Library with 4 LTO-5  tape drivers and configured 13th Client severs and all the backup are running very very slow at minimum 277 Kb/sec to Maximum 2560 Kb/sec, and i splited the backup selections and enabled Multistreaming and Multiplexing also still same problem, and by refering some document from "Mark" i did some chnages still same problem could any once suggest me how to increase the speed of the backup's ?

and NIC is set to 100 MB Full.


On each Media Server ensure that Program Files\veritas\netbackup\db\config\ exists (it doesnt by default)

in that directory create two files with no extension called SIZE_DATA_BUFFERS and NUMBER_DATA_BUFFERS

Open then using notepad and in the SIZE one put 262144 and in the NUMBER one put 32

Save the file (Making sure notepad doesnt add .txt on the end)

No need to re-start any services they take immediate effect next time you run a backup.

If you back up to disk you can use similar ones - just create another two files with _DISK on the end, you can use the same value for the number but a good value for the size for disk is 1048576

Hope this helps


Level 6
Partner Accredited Certified

"100 MB Full" means 100Mbps Full duplex, right? If so this can be the cause of slow backup. Are you running backup of multiple clients simultaneously? Does this fill up bandwidth of NIC?

Level 6

Hello ishikawa,

yes 100Mbps full duplex, yes running backup for multiple clients same time,

and i did got what yo are asking "Does this fill up bandwidth of NIC?.

if 100mBps full is the cause then what setting needs to be set please suggest.


Partner    VIP    Accredited Certified

yes 100Mbps full duplex

100Mbps means 100 Megabits per second =  ~ 10 Megabytes per second.

This means you can only receive data on the server at this speed, and then send data to 4 LTO tape drives?

A 1 Gb NIC (1000Mbps) can receive data at +- 100 MB/sec and will be able to stream to a single LTO tape drive (not 4...).

You also need to check how fast network clients can read data from disk and send across the network to the media server.

How to benchmark the performance of the bpbkar32 process on a Windows client

Overview of NetBackup performance testing.

Symantec NetBackup™ 7.0 - 7.1 Backup Planning and Performance Tuning Guide

About tuning Windows for NetBackup

Level 6

Hello Marianne,

i will follow the steps for bpbkr and others by tomorrow, mean while In my master/media server im not able to see IGB NIC, it seems server is supported only 100Mbps, in this case do we need to set this to "Auto",




Partner    VIP    Accredited Certified

Yes. For Gigabit NIC, choose Auto. This will still be able to only receive data at a speed that can stream a single LTO 4 tape drive.
You will need a 10Gb network for the amount of tape drives if this is your only media server.

Please have a look at rest of Performance Tuning docs as well.

Level 6

Also check your port setting on the switch to make sure it supports, and is set for, 1Gbit.  Other possible problems could be bad Ehternet cables, or a faulty NIC. 

According to the HP support site:

"Broadcomm lan cards (Network Interface Card or NIC) do not offer the gbit speed and duplex selection in the Windows drivers configuration because the Gigabit protocol negotiates this itself between two nodes to determine the Master/Slave role. Use the "AUTO" selection to set the proper GBit speed negotiation with network switches. There is no half or full duplex mode to configure. "

As Marianne stated above, a single gigabit NIC can only ingest data fast enough to stream data to a single LTO4 tape drive.  You have 4 LTO5 tape drives, which have an even higher requirement for streaming data to them.  You should look into upgrading your backup infrastructure to properly handle the data you are backing up.  Based on my experience, you really shouldn't have more than 2 or 3 LTO4 or higher tape drives per media server, unless you have a VERY high end media server (fast PCI slots, fast memory bus, fast everything).

I would suggest adding a second media server, and install two Gbit NICs in each media server.  Zone or connect only two drives to each media server.  And make sure your network infrastructure (switches and their ports) can handle that much data at once. 

Level 6

Hello Ron,

Yes our Master/Media(same) i shaving Dell TL4000 Library with LTO5 model(with 4 Tape Drives) is attached to to backup only 12 Client servers, still we need to go for secondary media server in this case?

and you are asking me to set the NIC for Switch side also  to "AUTO" right?

how we can check the NIC or Ehternet cable is bad with out replacing is it possible by any way ?