User's Manual

120 Migration, release, recall, and deletion
Migration retention time (MigRetentionTime)
Recall retention time (RecallRetentionTime)
Minimum file size for release (MinFileSize)
NOTE: Windows specific
On Windows platform, the recommended MinFileSize for release should not be smaller than the NTFS
file system cluster size (allocation unit). This is typically 4 KB for volumes larger than 2 GB. A lower
specified value would not free any additional disk space (the NTFS file system cluster size can be selected
when formatting NTFS volumes).
Files that are never released (ExcludeFromRelease)
TIP: If certain files or groups of files cannot be easily excluded from the release process using the
ExcludeFromRelease parameter, you can decrease their access times by setting the
RecallRetentionTime parameter in the FSE partition configuration to a higher value. Note that this
change affects all files on a particular FSE partition and may have undesired consequences, like reaching
high and critical watermarks on this FSE partition more frequently.
Example situations that trigger release
There are two distinct situations that trigger a new release job.
• Situation 1
A high watermark is reached on the HSM file system. At this point, all files on the release candidate list
larger than the MinFileSize variable value and with their retention time reached are scheduled for
Definition A period of time during which a certain file is going to be kept online after migration
before it will be released.
Impact Consider for how long a migrated file should stay online. Adjust the value according to
your data characteristics. If you use the partition for archiving purposes, the value should
be low. Partitions with frequently used files should have a higher value set, so that the files
do not get released and recalled all the time.
Definition A period of time during which a certain file is going to be kept online after recall before
it will be released again.
Impact Consider for how long a recalled file should stay online. If the specified time is too small,
such a file will be recalled every time it is accessed; if it is too long, it will take up disk
space without any reason.
Definition Minimum size for a file on the release candidate list to be regularly released. In case of a
forced release, this parameter is disregarded and files of all sizes will be released.
Impact It is not recommended to put very small files offline since the load of the library and
media in this case is rather significant whereas the disk space usage is hardly affected.
The recommended value is above 2 KB (default).
Definition A comma-separated list of filenames and filename patterns that defines a set of files that
will be skipped by the automatic release process. If the list is empty or this variable is not
configured, all files are considered for automatic release.
Impact The files covered by this parameter will not be released. Instead, they will be kept
permanently online, with their data residing on the HSM file system.