User's Manual

hp StorageWorks File System Extender User Guide 111
The way transitions between HSM lists and other aspects of migration, recall, release, and deletion are
controlled is defined by parameters in the configuration file for the FSE partition. These parameters are
described in ”Migration” on page 112, ”Release” on page 114, ”Recall” on page 121, ”Deletion” on
page 122, and in ”System allocation and job priority policy” on page 127 and ”Partition allocation and
job priority policy” on page 128.
The following graphic shows file-status changes, including transitions of file entries between FSE HSM lists.
The MinFileAge parameter is one of the configuration parameters for an FSE partition. It represents the
period of time during which a file must be left intact to become a migration candidate.
Figure 18 Changes of states of files under FSE
Example scenario of migration and release
The example presents how migration and release work according to specified policies.
1. A user has created a file and saved it is as myfile.doc, and he continued to work on the file.
Hierarchical Storage Manager (HSM) noticed the change and added myfile.doc to the dirty file list.
2. The user has stopped working on myfile.doc and closed it. After a predefined time to wait after file
change before migration, based on the migration policy parameter MinFileAge, the file is passed
from the dirty file list to the migration candidate list.
3. The time till migration is set to 20 minutes. After 20 minutes myfile.doc is migrated to media.
4. The file myfile.doc is then added to the release candidate list. When the used capacity of the HSM
file system exceeds a certain percentage, defined with a high watermark, for example 85%, HSM
triggers a corresponding release action. myfile.doc is released together with other files from the
release candidate list and is now offline.
About policies
FSE control over the files in use is based on user-defined policies. These are rules by which migration,
release, and deletion jobs are executed. Each process requires its own policy, thus migration policy,
release policy, and deletion policy. Each FSE partition has its own set of policies.
Different policies can be defined for individual FSE partitions, according to the partition’s purpose and the
way it is used. Policies are defined in FSE partition configuration files as a series of parameters. These are
read and used by the Hierarchical Storage Manager and the Partition Manager at startup (migration and
release policies) or at execution of the fsefile --trigger-deletion command (deletion policy).
The parameters are described in comments inside the FSE configuration file templates.
You need to plan in advance to set the policies according to your environment and to optimize the jobs.
The way you set up these policies will affect your FSE implementation’s performance.