Memoryefficientbackup

One method backs up one directory at a time, using less memory. The other method uses much less memory, but requires more disk space.

Use the memoryefficientbackup option with the incremental command when your workstation is memory constrained. You can also use this option as a parameter to the include.fs option in order to select the algorithm that the backup-archive client uses on a per-filespace basis.

Use memoryefficientbackup=diskcachemethod for any file space that has too many files for the client to complete the incremental backup with either the default setting, memoryefficientbackup=no, or with memoryefficientbackup=yes. The disk cache file created by the initial disk cache incremental backup can require up to 5 GB of disk space for each million files or directories being backed up.

Use memoryefficientbackup=diskcachemethod for any file space that has too many files for the client to complete the incremental backup with either the default setting, memoryefficientbackup=no, or with memoryefficientbackup=yes.

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 path 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 path 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.