User's Manual

136 Migration, release, recall, and deletion
regular release. The release job is stopped when the low watermark is reached or if there are no more
files on the release candidate list that match the specified criteria.
• Situation 2
A critical watermark is reached on the HSM file system. In this case, all files on the release candidate
list (regardless of their size and retention time) are scheduled for forced release. The release job is
stopped when the high watermark is reached or if there are no more files to release.
In both cases, the files that are on the release candidate list and were not released during the most recent
release job remain on the top of the release candidate list.
Default release policy
Note that the default release policy does not include the ExcludeFromRelease variable. If you do not
configure this variable, all files are considered for release according to the other release policy parameters
specified while configuring the FSE partition.
Default release policy is defined in the FSE configuration template for FSE partition configuration. For
details, see ”Template for FSE partitions - Release part” on page 303.
Recall
A recall job is started when an FSE user tries either of the following:
• read an offline file, write to it or change its attributes on an HSM file system (implicit recall)
• invoke the fsefile command to recall a single file, set of files or an older file generation (explicit
recall)
When a file recall is triggered, the contents of the file are retrieved from the FSE medium and copied back
to the HSM file system. The only parameter for the recall configuration is the timeout value.
Recall behavior is automated to the extent that recall is retried from alternative copies in cases that a
resource allocation is affected. This usually happens when a medium is corrupted and marked in the
Resource Management Database accordingly as unusable, or when a hardware error occurred and the
drive is marked as bad.
In such cases, the recall job requests new resources to perform the operation until reading from the tape is
successful, or all resources (media that contain respective data copies or drives) are exhausted. In this latter
event, the recall job fails.
NOTE: If an implicit recall lasts longer than specified with the RecallTimeOut parameter, an error
message is reported to the application that triggered the recall, but the recall job continues to run in the
background. Such behavior prevents applications from being blocked by lengthy recalls.
Using explicit recall, you can recall a single file, its older generations, or sets of files from FSE media to the
HSM file system. For information on how to explicitly recall a single file, see the fsefile man page. For
information on how to explicitly recall older file generations, see chapter ”Monitoring and maintaining
FSE”, section ”Recalling older generations of a file” on page 160. For information on how to efficiently
recall large sets of files, see chapter ”Monitoring and maintaining FSE”, section ”Recalling sets of files in
an efficient way” on page 162.
Recall parameters
There is only one configurable parameter for the recall policy.