Diskcachelocation

You can specify the diskcachelocation option in your option file, or with the include.fs option. If the diskcachelocation option appears in the option file, its value is used for all file systems not represented by an include.fs option containing the diskcachelocation option.

The disk cache is a temporary file which is deleted after the incremental command is run. Use this option to select one of the following:

1. A location that has more free disk space if, when you are using memoryefficientbackup=diskcachemethod, you get the message that the disk cache file cannot be created because you do not have enough disk space.
2. A location on a different physical volume to reduce contention for the disk access mechanism, and therefore improve performance.

The actual amount of disk space required for the disk cache file created by disk cache incremental backups depends on the number of files and directories included in the backup and on the average length of the files and directories to be backed up. For UNIX and Linux, estimate 1 byte per character in the path name. For Mac OS X, estimate 4 bytes per character in the path name. For example, if there are 1 000 000 files and directories to be backed up and the average path length is 200 characters, then the database occupies approximately 200 MB for UNIX and Linux, and 800 MB for Mac OS X clients. Another way to estimate for planning purposes is to multiply the number of files and directories by the length of the longest path to establish a maximum database size.

The actual amount of disk space required for the disk cache file created by disk cache incremental backups depends on the number of files and directories included in the backup and on the average length of the files and directories to be backed up. Estimate 2 bytes per character in the path name. For example, if there are 1 000 000 files and directories to be backed up and the average path length is 200 characters, then the database occupies approximately 400 MB. Another way to estimate for planning purposes is to multiply the number of files and directories by the length of the longest path to establish a maximum database size.

A second disk cache file is created for the list of migrated files when backing up an HSM managed file system. The combined disk cache files, created by disk cache incremental backups and HSM managed file system backups, can require above 400 MB of disk space for each million files being backed up. The disk cache file can become very large. Large file support must be enabled on the file system that is being used for the disk cache file.

Supported Clients

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

Options File

Place this option in the client options file (dsm.opt).

Place this option in the dsm.sys file within a server stanza.

Parameters

path

Specifies the location where the disk cache database is created if memoryefficientbackup=diskcachemethod. The default location is to create the disk cache file in the root of the file space being processed.

In Uniform Naming Convention (UNC) format, the path must contain a drive letter. In the following UNC format example, the path contains the drive letter D$: \\computer7\D$\temp\diskcache.