Best Practices

Compression in Bacula

Hardware and software data compression and communication line compression between daemons can be used independently from each other.

Hardware Compression

Hardware compression by tape drives is not directly configured through Bacula configuration files. Instead, it can be enabled or disabled with your tape drive, library, or the operating system following the vendor’s instructions.

The default for most tape drives is to have compression enabled. It is strongly advised to keep this default value enabled, as hardware compression is usually faster and more efficient than software compression.

Bacula’s software compression is configured in FileSet Include Options, can be controlled in a finely granular manner, and is independent from hardware compression. Combining both is usually not a good choice. When software compression is configured for some data, but needs to be disabled for backups going to particular storage, such as tape, the directive AllowCompression in the Director’s Storage resources is available.

Communication Line Compression

Regarding “Communication Line Compression”, Bacula Enterprise uses compression between daemons by default. It is advised to keep it enabled. If for any reason you need to disable this feature, you can do this by configuring Comm Compression = no. Refer to the directive Comm Compression. Note that the directive can be found in the DIR, the SD, the FD and the Console.

The compression algorithms used and the libraries implementing it are well tuned on x86 / AMD64 hardware, but often inefficient on other systems. In particular on RISC CPUs (Sparc or Power, for example) it may be better to disable this function.