WHERE FILE_SIZE > 5242880 AND (CURRENT_TIMESTAMP - MODIFICATION_TIME > INTERVAL '5' MINUTES) AND is_resident AND NOT user_exclude_list define(user_exclude_list,(PATH_NAME LIKE '/ibm/gpfs/.ltfsee/%' OR PATH_NAME LIKE  '/ibm/gpfs/.SpaceMan/%')) define(is_premigrated,(MISC_ATTRIBUTES LIKE '%M%' AND MISC_ATTRIBUTES NOT LIKE  '%V%')) define(is_migrated,(MISC_ATTRIBUTES LIKE '%V%')) define(is_resident,(NOT MISC_ATTRIBUTES LIKE '%M%')) RULE 'SYSTEM_POOL_PLACEMENT_RULE' SET POOL 'system' RULE EXTERNAL POOL 'LTFSEE_FILES' EXEC '/opt/ibm/ltfsee/bin/ltfsee'  OPTS '-p primary@lib_ltfsee copy@lib_ltfsee copy2@lib_ltfsee' SIZE(20971520) RULE 'LTFSEE_FILES_RULE' MIGRATE FROM POOL 'system' THRESHOLD(80,50) WEIGHT(CURRENT_TIMESTAMP - ACCESS_TIME) TO POOL 'LTFSEE_FILES' WHERE FILE_SIZE > 5242880  AND is_premigrated AND NOT user_exclude_list Example 8-9 failsafe_policy.txt Example 8-9 shows a simple  failsafe_policy.txt , which gets triggered when the IBM  Spectrum Scale disk space reaches 80% full, and stubs least recently used files until the disk  space has 50% occupancy. After setting the policy with the  mmchpolicy  command, run  mmaddcallback  with the fail-safe  policy. This policy runs periodically to check whether the disk space has reached the  threshold where stubbing is required to free up space.  The second policy is a fail-safe policy that needs to be set so when a low disk space event is  triggered, the fail-safe policy can be called. Adding the  WEIGHT  attribute to the policy enables  the user to choose whether they want to start stubbing large files first or least recently used  files. When the fail-safe policy starts running, it frees up the disk space to a set percentage. The following are the commands for setting a fail-safe policy and calling  mmadcallback : GLYPH<SM590000> mmchpolicy gpfs failsafe_policy.txt GLYPH<SM590000> mmaddcallback MIGRATION --command /usr/lpp/mmfs/bin/mmapplypolicy --event  lowDiskSpace --parms “%fsName -B 20000 -m <2x the number of drives>  --single-instance” Chapter 8. Hints, tips, and preferred practices  237