Chapter 6 HPSS Configuration
HPSS Installation Guide September 2002 281
Release 4.5, Revision 2
Before deleting a basic migration policy, make sure that it is not referenced in any storage
classconfigurations. If a storage class configuration references a migration policy which does
not exist, the Migration/Purge and Bitfile Servers will not start.
When a migration policy is added to or removed from a storage class configuration, the
Migration/PurgeServers must be restarted in order for migration to begin or end on this storage class. It is
not possible for Migration/Purge Servers to reread a migration policy for a storage class if the migration
policy was not assigned to the storage class when the Migration/Purge Server was started. Likewise, if a
migrationpolicy is removed from a storage class configuration, rereading the migration policy for this storage
classwill not cause the Migration/Purge Server to stop migrating this storage class. It is necessary to recycle
the Migration/Purge Servers when a storage subsystem specific migration policy is added or removed. It is
also necessary to recycle when a storage class configuration is changed to use a different migration policy.
Before changes made to a migration policy take effect, the Migration/Purge Servers must be either restarted
or instructed to reread the policy from theMPS Storage Class Information window. If the Migration/
Purge Servers are restarted, the changes to the migration policy are applied to all storage classes which
reference the policy. If the policy is reread, the changes are only applied to the storage class and storage
subsystemfor which the policy is reread. It is not necessary to recycle Bitfile Servers when the parameters in
a migration policy are changed.
Whena migration policy isadded to or removed from a storage class configuration, the Bitfile Servers must
be restarted in order for this change to take effect. If the Bitfile Servers are not restarted after a migration
policyhas been added to a storageclass configuration, migration records will not be created for files written
into the storage class. These files will never be able to migrate even after the Bitfile Servers are restarted. If
the Bitfile Servers are not restarted after a migration policy has been removed from a storage class
configuration, migration records will continue to be created for files written into this storage class. These
migration records will become orphaned metadata since migration is no longer supported on this storage
class. It is also necessary to restart the Bitfile Servers if a storage class configuration is changed to use a
different migration policy. It is not necessary to restart the Bitfile Servers if a storage subsystem specific
migration policy is added or removed.
Referto the window's help file for more information on the individual fields and buttons as well as
the supported operations available from the window.