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NET BUFFER VALUES

PARDHU
Level 2
Hi,
 
In our environment we are using a dedicated 1GB backup lan and we are using IBM LTO2, LTO3 tape drives. While taking the backups for some wintel clients the tape drives are writing with very less speed like below 1mb/sec. Any one could you please let me know how to set the net buffer values in the media server and clients and what's the recomanded values do we have to use media servers and in the clients.
 
Could you please let me know is there any difference in these values for LTO2 and LTO3 drives
5 REPLIES 5

Stumpr2
Level 6
Pardhu,
Please look through this manual/guide. It not only tells how to setup the tuning but there is also a section that helps you determine potential bottlenecks through the entire backup/restore data flow.
 
Veritas NetBackup (tm) Enterprise Server / Server 6.0 Backup Planning and Performance Tuning Guide for UNIX, Windows, and Linux. And 6.0 MP5 updates for NetBackup Operations Manager (NOM).
 
 

Stafford
Level 4
See if your NIC is set to half duplex.

Omar_Villa
Level 6
Employee
Try this:
 
Get the buffers setting from /usr/openv/netbackup/db/config
 
NET_BUFFER_SZ = 262144
NUMBER_DATA_BUFFERS = 128
SIZE_DATA_BUFFERS = 262144
 
SIZE_DATA_BUFFERS * NUMBER_DATA_BUFFERS * (NUMBER_OF_DRIVES * MPX)
262144 * 128 * (64 * 4) = 8192MB
 
grep -i shm "/etc/system"
set shmsys:shminfo_shmmax=6492782592
set shmsys:shminfo_shmmin=1
set shmsys:shminfo_shmmni=512
set shmsys:shminfo_shmseg=100
 
compare the total with the Shared Memory info and if is need perform the proper changes.
 

Buffers management

http://seer.entsupport.symantec.com/docs/245920.htm

http://www.adsm.org/lists/html/Veritas-bu/2004-03/msg00217.html

http://seer.entsupport.symantec.com/docs/244652.htm

Regards

PARDHU
Level 2
Hi,
 
I am sorry I forgot to update the VNB version.
We are using the VNB 5.0 MP7, and in the master server and in the media servers and in all the clients the backup nic speed is set to AUTO and it's a IGBPS dedicated backup lan.
 
I try to use the SIZE_DATA_BUFFERS = 262144, but after creating this file under /usr/openv/netbackup/db/config the backups are failing with status code 84 and the tape drive is going offline.

Omar_Villa
Level 6
Employee
well 84 errors point more to a hardware issue with your drives or probably with your tpconfig, autoconf and vmglob configuration I think should check with IBM probably there is an issue with this drives, do u have the last firmware on this ones?