Netbackup 7.1 - Image file size

[JohnKnittl]

When we backup our file server of 750GB to disk it creates 2 img files. the first is 524GB and the second is 225GB.

Is there a setting on how big the image file gets before it starts a new file.

We have found that our backup slows down as the img file gets bigger and we see a performance increase when the new file is created.

Thank you

JK

[Marianne · Accepted solution]

This is controlled by the Fragment size in the Storage Unit Properties.

The default is 524,288 megabytes.

Fragment size can be reduced, but a slow-down will be probably be noticed when one img file is 'closed off' and a new one is created..

[JohnKnittl]

Thank you for the quick reply.

Should I see a performance drop as the img file gets larger ? Or am I looking in the wrong spot as to why my backups are going slow.

[Marianne]

It is normal to see slow down when one img file is 'closed off' and a new one is created..

Backups of file servers are usually slow because of disk fragmentation, directory depth, lots of small files (hardly ever the backup destination).

Some good reading matter:

Overview of NBU performance testing: http://www.symantec.com/docs/TECH147296

(See Related Articles as well)

About tuning Windows for NetBackup : http://www.symantec.com/docs/HOWTO56210