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Compressed Backup bigger than Original Database??

waynephwayneph Posts: 29
edited December 4, 2007 1:58AM in SQL Backup Previous Versions
This is a strange one. I just installed SQL Backup 5.2 (Build 2825) on to one of my SQL 2000 servers. I backed up all of the databases, and most of them had compression rates between 85 and 95%. A couple of the slightly larger ones only got 80%, but still pretty good.

However there was one database that actually had a -6% Compression... The database is 17.3 GB, but backed up to an 18.3 GB file. Obviously everything is installed correctly on the server, and since all of the backups were from a single job, the compressions setting didn't change between databases.

Is there anything in the database that I can look at to try and figure this out? I ran a DBCC CHECKDB() on the database and it didn't report any errors. The database is from a 3rd party vendor, but other than that, I can't think of anything special. The database is in the FULL Recovery Model and the Transaction log is under 300MB and gets backed up regularly.

Thanks for any suggestions...


  • Options
    peteypetey Posts: 2,358 New member
    If the database contains pre-compressed data e.g. zipped archives, png image files, jpeg image files, there is a possibility that compression level 1 results in a larger file. In these cases, you could try using compression level 2 and see if it results in a smaller file. If the space saving is not significant, I would suggest using native SQL Server backups then. If you are also encrypting the file, then use compression level 0.
    Peter Yeoh
    SQL Backup Consultant Developer
    Associate, Yohz Software
    Beyond compression - SQL Backup goodies under the hood, updated for version 8
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