All files to be migrated must have more than 5 MB of disk space that is allocated for the file (see the KB_ALLOCATED  attribute). The migration is performed to an external pool, presented by IBM Spectrum Archive EE ( /opt/ibm/ltfsee/bin/ltfsee ), and the data that is migrated is sent to the IBM Spectrum Archive EE tape cartridge pool named Tapepool1 . In addition, this example policy excludes some system files and directories. 

define ( exclude_list, ( PATH_NAME LIKE '%/.SpaceMan/%' OR PATH_NAME LIKE '%/.ctdb/%' OR PATH_NAME LIKE '/ibm/glues/.ltfsee/%' OR NAME LIKE 'fileset.quota%' OR NAME LIKE 'group.quota%' ) ) RULE EXTERNAL POOL 'ltfsee' EXEC '/opt/ibm/ltfsee/bin/ltfsee' OPTS -p‘Tapepool1' /* This is our pool in LTFS Enterprise Edition */ SIZE(20971520) /* The following statement is the migration rule */ RULE 'ee_sysmig' MIGRATE FROM POOL 'system' THRESHOLD(80,60) WEIGHT(CURRENT_TIMESTAMP - ACCESS_TIME) TO POOL 'ltfsee' WHERE (KB_ALLOCATED > 5120) AND NOT (exclude_list) /* The following statement is the default placement rule that is required for a system migration */ RULE 'default' set pool 'system' 

In addition to monitoring the file system’s overall usage in Example 7-60, you can monitor how frequently a file is accessed with IBM Spectrum Scale policies. A file’s access temperature  is an attribute for a policy that provides a means of optimizing tiered storage. File temperatures are a relative attribute, which indicates whether a file is “hotter” or “colder” than the others in its pool. 

The policy can be used to migrate hotter files to higher tiers and colder files to lower. The access temperature is an exponential moving average of the accesses to the file. As files are accessed, the temperature increases. Likewise, when the access stops, the file cools. File temperature is intended to optimize nonvolatile storage, not memory usage. Therefore, cache hits are not counted. In a similar manner, only user accesses are counted. 

The access counts to a file are tracked as an exponential moving average. A file that is not accessed loses a percentage of its accesses each period. The loss percentage and period are set through the configuration variables fileHeatLossPercent  and fileHeatPeriodMinutes . By default, the file access temperature is not tracked. 

