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.
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.
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.
- LZ4
- A faster and more efficient compression method that the client uses in any of the following situations:
- The client-side deduplicated-object is sent to a container storage pool on the IBM Spectrum® Protect server. The server must be at version 7.1.5 or later.
- The object 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-side deduplicated-data can be compressed.)
- The object 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-side deduplicated-data can be compressed.)
- LZW
- A traditional type of compression that the client uses is when client-deduplicated objects are sent to traditional (non-container) storage pools on the server.
- 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.
Supported Clients
This option is valid for all clients. The server can also define this option.
Options File
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.
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
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.