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hcart2 MPX question

manatee
Level 6

NBU 7.6.0.3

i am having issues with backup performance and am looking at the default settings the vendor configured for our NBU server. in another thread, someone suggested that i have a look at max jobs per client, multiplexing, and STU (i still have to find what STU means :) ).

in my tape drive i found:

robot type: TLD

density: hcart2

max concurrent drives: 2 (i do have only 2 tape drives)

multiplexing is disabled but with a greyed out value of "1". fragment size is 1048575

with the above findings, if i want to increase backup performance should i change the values like enable multiplexing (my max jobs per client is now 4 from 99) ?

if i do change the data streams number, what should i do to make a configuration backup first of NBU in case the changes doesn't work and i want to restore the previous settings?

2 ACCEPTED SOLUTIONS

Accepted Solutions

Nicolai
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There is a excellent part covering performance in the Netbackup Backup planing and performance tuning guide

http://www.symantec.com/docs/DOC7449

I would advise to to configure Netbackup BPTM buffers before changing MPX setting.

in [install_path]/netbackup/db/config

Create a file called NUMBER_DATA_BUFFERS (no extension like .txt at all). Put the value 256 in it. This tweak is documented in the "Netbackup Backup planing and performance tuning guide" but I would mention it here bacuase it really do a diffrence.

 

 

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Marianne
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As per my reply in your other post, we have found that a value of 4 in Max Jobs per Client, MPX of 4 in STU and MPX of 4 in Policy schedules give good backup and restore performance.

I have seen customers going with higher values and still claim good backup and restore performance.

About making changes:

Document each change.
Go slow on Policy changes - one or 2 at a time.
Record value of setting(s) performance before the change and after the change.

This way it is easy to know when the change(s) did not have the desired effect and you will know what to change back.

Ensure bptm log folder exists on all media servers in order to track down and troubleshoot the bottleneck.

More reading matter: 

NetBackup 7.6 Best Practices: Optimizing Performance

Updated NetBackup Backup Planning and Performance Tuning Guide for Release 7.5 and Release 7.6 

View solution in original post

6 REPLIES 6

Marianne
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STU is a Storage Unit.

Please see these links in my reply to your other post: 
https://www-secure.symantec.com/connect/forums/bmr-backup-backup-length#comment-10899401

Nicolai
Moderator
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There is a excellent part covering performance in the Netbackup Backup planing and performance tuning guide

http://www.symantec.com/docs/DOC7449

I would advise to to configure Netbackup BPTM buffers before changing MPX setting.

in [install_path]/netbackup/db/config

Create a file called NUMBER_DATA_BUFFERS (no extension like .txt at all). Put the value 256 in it. This tweak is documented in the "Netbackup Backup planing and performance tuning guide" but I would mention it here bacuase it really do a diffrence.

 

 

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

As per my reply in your other post, we have found that a value of 4 in Max Jobs per Client, MPX of 4 in STU and MPX of 4 in Policy schedules give good backup and restore performance.

I have seen customers going with higher values and still claim good backup and restore performance.

About making changes:

Document each change.
Go slow on Policy changes - one or 2 at a time.
Record value of setting(s) performance before the change and after the change.

This way it is easy to know when the change(s) did not have the desired effect and you will know what to change back.

Ensure bptm log folder exists on all media servers in order to track down and troubleshoot the bottleneck.

More reading matter: 

NetBackup 7.6 Best Practices: Optimizing Performance

Updated NetBackup Backup Planning and Performance Tuning Guide for Release 7.5 and Release 7.6 

Marianne
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Another 2c from my side...

density: hcart2 does not have any other value than keeping device types together - tape drives, media, STU.

NBU will assign hcart2 density to both LTO2 and LTO5 drives and media.

You need to find out what the actual hardware is and then read the specs for it. 
You will see in the tape drive documentation what the speed you can expect from the drive and what the minimum transfer rate is in order to keep drive streaming and prevent shoe-shining.

If you are not seeing these transfer rates, you need to examine all components in the backup path - from client disk up to the tape drive.

The Performance Tuning Guide is a good source of information. 
Unfortunately no 'magic wand'  -  baby steps to troubleshoot and pinpoint bottleneck...

manatee
Level 6

lots of good reading here :)

 

thank you all for the replies.

 

note: can't mark more than one solution so i'm not marking any one, yet all of you provided good materials

Marianne
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'Request split solution ' allows you to mark more than one solution.