Netbackup compression

[shashi0621]

Hi Guys.

I have read a lot about compression.IN NBU admin guides also and in the forums.

SOftware compression is not encouraged.

I know that NBU will backup the compressed files as it is.It does not decompress before backing it up.

Now  on a Windows OS,I have  a compressed folder.:

1.what happen if compresed option is checked in policy? will that folder be decompress first ,then NBU will read the data..is it?

2.if not checked in policy?

Now  on a Windows OS,I have  a  folder.:

3.what happen if compresed option is checked in policy? decompression occurs here before backup?

4.if not checked in policy?

NBU 7.5

[Nicolai]

Have you tried it out ?

Best way to learn is by doing ....

[shashi0621]

Hi Nicolai..I have tried but have not figure it out.PLease halp me on this.thanks.Will be greatful to you.

[revarooo]

NetBackup will not decompress any files it is backing up.

[shashi0621]

I have read this:

http://www.symantec.com/business/support/index?page=content&id=TECH34346

NT File System (NTFS) compression can save disk space, but compressing data can adversely affect backup and restore performance. When backing up a compressed NTFS file, NTFS first decompresses the files, then the backup software copies the files to either tape or disk and the files will be re-compressed if either hardware or software compression is enabled within the backup application.

[revarooo · Accepted solution]

Hence, NETBACKUP does not decompress any files before backing them up
 

[sdo]

A backup of NTFS compressed (native/embedded within the NTFS file-system) files (typically coloured blue in Windows Explorer) will have to uncompress said files (on the fly) as they are read - during a backup such files are not uncompressed on disk, nor re-compressed - the effect is that every time a 'compressed' file is read (e.g. by a backup) more CPU (and a liitle RAM) is consumed by the very act of reading (i.e. backing up the file) - this is not the same as backing up a zip file, which is backed-up in its "compressed" form. As Nicolai has suggested, you could try testing (with non-production data)... use of the DOS CLI command named "compact" will help you to create "compressed" NTFS files and folders trees. IMO, it is a liitle bit unfortunate that we all seem to refer to this as NTFS "compression", whereas the the more accurate term is NTFS "compaction", hence the command that manages this at the CLI level is the command named "compact". So, the true process is that NTFS compacted files are de-compacted, within RAM by the CPU, by the NTFS file-system driver - as the compacted file blocks are read from disk - before the decompacted file blocks are passed (from RAM based NTFS buffers) to the application (RAM based buffers) performing the file read - e.g. the backup appliaction, or indeed any other tool or appliaction or command (word, excel, notepad, wordpad, type, for, sort, bpbkar32, etc...).