Software Compression Not Happening

[tasukete99]

I just backed up my Windows XP system with Retrospect Pro 7.5.370 / Drivers & Hot Fix 7.5.10.104 to a file on a USB2-attached hard drive with NTFS for the first time after upgrading from 6.0 to 7.5. I was astonished at the size of the "Backup Set A.rbf" file, and when I looked the log, the compression was 0% even though I had the software compression option checked. Any thoughts what could be the problem?

Thanks.

 

Here's the Log entry:

 

- 4/19/2008 11:29:03 AM: Copying Local Disk (C:)

4/19/2008 2:04:00 PM: Snapshot stored, 102.9 MB

4/19/2008 2:04:23 PM: Comparing Local Disk (C:)

4/19/2008 3:56:38 PM: Execution completed successfully

Completed: 138356 files, 66.0 GB, with 0% compression

Performance: 520.0 MB/minute (457.9 copy, 601.7 compare)

Duration: 04:27:35 (00:07:51 idle/loading/preparing)

 

 

Edited April 19, 2008 by Guest

[Mayoff]

Compression is working, you are just getting zero percent on average.

 

http://kb.dantz.com/article.asp?article=5618&p=2

 

Edited April 20, 2008 by Guest

[MRIS]

Also backing up to a USB attached external hard drive, you are much better advised to use a DISK based backup set (rather than a file), because then you get the magic of grooming and other features. This allows tou to continually backup to the same disk and it automatically keeps the most recent backups and gradually cleans away the older ones.

[tasukete99]

Thanks. I would never have considered that, butI guess it's true, because last night a scheduled incremental got 38% compression.

 

Years ago when I first started using Retrospect, there was a reason why I chose File rather than Disk as the backup option, but I can't remember any more what it was, so maybe I'll switch. Thanks.

Edited April 21, 2008 by Guest

[mlts22]

The advantage of file based backup sets is that the data is stored in a single file, as opposed to a disk and the directory structure.

 

For some things, such as a fresh system image, or data that I plan to cryptographically sign to make sure it won't be altered in the future, I'll use a file backup. Almost anything else, I will use disk for its flexibility.

[dthede]

As others have stated, I also have a backup script (back to disk) which specified Backup Set compression. When looking at the Op Log History Tab, however, it shows zero percent compression. I've gone back and checked the script to verify that my SOP of using compression was indeed selected. The target Volume being backed up is spongy so I would expect about 30% compression, as on other backups for this volume under a different script, not zero. Any helpful thoughts regarding software compression under Retrospect version 7.5.14.102 in the Win XP Pro SP2 environment?

(The response that there is simply 0% compression on average is not helpful, since the same target files typically report back 29% compression under the original script.)

Since this is a first backup under a new script, (All Files selected) it's easy to compare bytes backed up in the Backup Set to the bytes in the source Volume.