Guys,what is the meaning of "Fragment Size" that we specify in storage units of NBU ?...
what if it is more and what is less..also,why it is by default always maximum ?
When Netbackup write a backup image it marks in the catalog what fragment a file is located.
Larger fragment mean smaller catalog overhead but longer restore time.
Small fragment mean short restore times, but more catalog overhead.
If you request a single file with a unlimited fragment size netbackup will read the entire image to find the file. However if the fragment size is e.g. 50GB only those 50GB where is file is located is read. Think a fragment as a storage box, you can have one very big one or a lot of small ones. Normally is easyer to find thing in small boxes that one 50 feet container (without light).
I typical go for a 50GB fragment size for tape and 8GB for disk.