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Does NetBackup, restores sparse data as original data.

I backuped a large amount of sparse data, it occupies very little space on the source, but when I restored the data it occupies full space same as the size of sparse data.

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Here is an article for your

Here is an article for your reference.

https://www-secure.symantec.com/connect/articles/accelerator-backup-sparse-file

As it said, sparse file has two size, one is logical size, other is physical size. NetBackup only backups the actual physical non-zero data to server, when restore data, i think, it would occupy the logical size.

Can you compare the restored data to the original data to see if they are identical?

Thanks

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Can you elaborate on

Can you elaborate on that.

What version if Netbackup

What client OS

What Netbackup client type (Windows, Oracle, UNIX, Flash-backup etc)

Consider to do a bppllist -U NAME_OF_POLICY and attach the output as a file to the next post. This will help us understand the issue.

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Netbackup 7.6 Client OS

Netbackup 7.6

Client OS Windows2003

Netbackup client type Windows

I am explaining further

1. I created a iscsi lun. Mapped it on windows machine.

2. Created sparse data on that lun.

3. Backed up the lun, on tape library.

4. While restoring it is considering sparse data as original data and consuming large amount of space.

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Please tell us what exactly

Please tell us what exactly this 'sparse' data is? 

I thought it was a dedupe volume on a W2012 client, but not possible with W2003.

Even with W2012 dedupe volume, the NBU documentation says that data is rehydrated (full size) when restored.

Probably the same in this case.

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Sparse data is created using

Sparse data is created using "fsutil.exe", inbuilt tool of windows.

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Accepted Solution!

Here is an article for your

Here is an article for your reference.

https://www-secure.symantec.com/connect/articles/accelerator-backup-sparse-file

As it said, sparse file has two size, one is logical size, other is physical size. NetBackup only backups the actual physical non-zero data to server, when restore data, i think, it would occupy the logical size.

Can you compare the restored data to the original data to see if they are identical?

Thanks

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I missed your question what

I missed your question

what exactly this 'sparse' data is? As already suggested by Walker, Basically sparse data occupies more disk space then it's actual size. So, sparse data  basically contains zero filled file or empty file occuping a large on disk space. So, they occupy space more efficiently. So, when we compress a sparse file, it's size become too small.

 

Can you compare the restored data to the original data to see if they are identical? >> yes, they are identical, they are of the same size also.

 

 

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So we could consider it as

So we could consider it as expected.

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Yes may be, I think it is

Yes may be, I think it is just looking to iscsi as a file of a particular size, and not looking to the data inside it.