Compression

The compression option compresses files before you send them to the server.

Compressing your files reduces data storage for backup versions and archive copies of your files. It can, however, affect IBM Spectrum Protect™ throughput. A fast processor on a slow network connection benefits from compression, but a slow processor on a fast network connection does not.

Use the compression option with the archive, incremental, and selective commands.

AIX operating systems Linux operating systems Oracle Solaris operating systems The backup image command uses the compression option value specified in the dsm.sys file. This option is valid on the initial command line and in interactive mode. The server can also define this option which overrides the client value.

Windows operating systems The backup image command uses the compression option value specified in the dsm.opt file. This option is valid on the initial command line and in interactive mode. The server can also define this option which overrides the client value.

The backup-archive client backs up a sparse file as a regular file if client compression is off. Set compression yes to enable file compression when backing up sparse files to minimize network transaction time and maximize server storage space.

If you set compressalways yes, compression continues even if the file size increases. To stop compression if the file size grows, and resend the file uncompressed, set compressalways no.

If you set compression yes, you can control compression processing in the following ways:

Use the exclude.compression option in your client options file (dsm.opt) to exclude specific files or groups of files from compression processing.
Use the exclude.compression option in your client system-options file (dsm.sys) to exclude specific files or groups of files from compression processing.
Use the include.compression option in your client options file (dsm.opt) to include files within a broad group of excluded files for compression processing.
Use the include.compression option in your client system-options file (dsm.sys) to include files within a broad group of excluded files for compression processing.

This option controls compression only if your administrator specifies that your client node can compress files before sending them to the server.

The type of compression that the client uses is determined by the combination of compression and client-side data deduplication that is used during backup or archive processing. The following types of compression are used:

LZ4

A faster and more efficient compression method that the client uses when client-deduplicated data is sent to an LZ4-compatible container storage pool on the IBM Spectrum Protect server. The server must be at version 7.1.5 or later, and must use container storage pools. Client-side LZ4 compression is used only when client-side data deduplication is enabled.

LZW

A traditional type of compression that the client uses in any of the following situations:

Client-deduplicated data is sent to traditional (non-container) storage pools on the server.
The client data does not undergo client-side data deduplication. (Does not apply to Data Protection for VMware and Data Protection for Microsoft Hyper-V, in which only client-deduplicated data can be compressed.)
The client data undergoes only traditional server-side data deduplication. (Does not apply to Data Protection for VMware and Data Protection for Microsoft Hyper-V, in which only client-deduplicated data can be compressed.)

None

The object is not compressed by the client. The object is not compressed because the compression option is set to no, or the option is not specified during backup or archive processing. Although the object is not compressed by the client, it might be compressed by the server.

You do not need to set the compression type. It is determined by the backup-archive client at the time of backup or archive processing.

Supported Clients

This option is valid for all clients. The server can also define this option.

Options File

AIX operating systems Linux operating systems Mac OS X operating systems Oracle Solaris operating systems Place this option in the dsm.sys file within a server stanza. You can set this option on the Backup tab, Compress objects check box of the Preferences editor.

Windows operating systems Place this option in the client options file (dsm.opt). You can set this option on the Backup tab, Compress objects check box of the Preferences editor.

Syntax


                .-No--.   
>>-COMPRESSIon--+-----+----------------------------------------><
                '-Yes-'

Parameters

No: Files are not compressed before they are sent to the server. This is the default.
Yes: Files are compressed before they are sent to the server.

Examples

Options file:: compression yes
Command line:: -compressi=no

This option is valid only on the initial command line. It is not valid in interactive mode.