Encrypting and compressing backups

Just found this. Common sense really but handy to know.

http://seer.entsupport.symantec.com/docs/285648.htm

"When using encryption it is not recommended to use hardware compression. If the data must be compressed it is recommended to use software compression. When using software compression the data is compressed first then encrypted. When using hardware compression the data is encrypted first then compressed. Encrypted data does not compress well because the data is randomized. In some cases using hardware compression with encryption will cause the data to become bigger rather than smaller."

Basically we created a new encrypted backup job, but left it to Hardware compression only. Needless to say the job was not compressed and so did not fit on to the tape. Have now changed the job to use software compression.