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Compression Switch Not Being Honored

I'm using SQL Backup to backup my databases to an EMC DataDomain server. This server De-Duplicates the data for maximum storage, but only if the backup files are not compressed.

My backup logs look like the data is being compressed even though I have compression = 0. Is this a bug?

Here is part of my backup job log file.

========
-SQL "BACKUP DATABASES [Ad_Hoc_SS_Tables_RCSQL,Billing,DEMOGRAPHIC,EMSReports,FORMS,PPAPI,RCSQL,RNEnterprise,RNEventing,UDXMapping,ZOLLOnlineSyncService] TO DISK = '\\dd640-1\backup\CADBILLSQL-SQL-FULL\<AUTO>.sqb' WITH ERASEFILES = 90, MAILTO = 'jpennington@xxxx.com', CHECKSUM, DISKRETRYINTERVAL = 30, DISKRETRYCOUNT = 10, COMPRESSION = 0, THREADCOUNT = 7 "
PROCESSES COMPLETED SUCCESSFULLY

6/7/2014 12:00:01 AM: Backing up Ad_Hoc_SS_Tables_RCSQL (full database) to:
6/7/2014 12:00:01 AM: \\dd640-1\backup\CADBILLSQL-SQL-FULL\FULL_(local)_Ad_Hoc_SS_Tables_RCSQL_20140607_000001.sqb

6/7/2014 12:00:02 AM: BACKUP DATABASE [Ad_Hoc_SS_Tables_RCSQL] TO VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A53', VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A5301', VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A5302', VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A5303', VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A5304', VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A5305', VIRTUAL_DEVICE = 'SQLBACKUP_FC656892-C8A3-492A-9AA1-0E04F3AE2A5306' WITH BUFFERCOUNT = 28, BLOCKSIZE = 65536, MAXTRANSFERSIZE = 1048576, NAME = N'Database (Ad_Hoc_SS_Tables_RCSQL), 6/7/2014 12:00:01 AM', DESCRIPTION = N'Backup on 6/7/2014 12:00:01 AM Server: CADBILLDB Database: Ad_Hoc_SS_Tables_RCSQL', FORMAT, CHECKSUM

6/7/2014 12:00:02 AM: Database size : 20.375 MB
6/7/2014 12:00:02 AM: Compression rate : 35.27%
jpenn727
0

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  • petey
    The compression rate is calculated on the actual amount of data stored in the backup files compared to the database size. The compression rate of 35% probably indicates that your database files have about 35% unused space, which SQL Server did not need to back up.
    petey
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  • jpenn727
    Thank you Pete, I did not know that.
    Jim
    jpenn727
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