6.3.5. Changing a File's C lass of Service
The Core Server provides a means to change the class of service of a file. The Core Server moves the
body of the file as appropriate to media in the destination Class of Service, t hen allows the usual
migration and purge algorithms for the new Class of Service to apply. The file body is removed from the
media in the old Class of Service. If large numbers of files on tapes are changed, an opportunity to reti re,
repack and/or reclaim tapes in the old Class of Service may arise.
The scrub utility can be used to initiate the COS change request of a file as follows:
% scrub
scrub> changecos <fullPathname> <newCOSid>
scrub> quit
6.3.6. Canceling a Class of Service Change Request
A Class of Service change request can be canceled in order to deal with a persistent problem in changing
the file.
The scrub utility can be used to cancel the COS change request as follows:
% scrub
scrub> changecos <fullPathname> 0
scrub> quit
The associated Core Server COS change record will be removed immediately. However, this request may
fail if the existing COS change request is currently being processed by one of the Core Server’s COS
change threads. In this case, the user should attempt to reissue the request later.
6.4. Migration Policies
A migration policy is associated with a storage class and defines the criteria by which data is migrated
from that storage class to storage classes at lower levels in the storage hierarchie s. Note, however, that it
is the storage hierarchy definitions, not the migration policy, which determine the number and location of
the migration targets. Also, note that a storage class may be used in multiple hierarchies and may have
different migration targets in each.
A basic migration policy must be assigned to any disk or tape storage class that requires migration
services. This basic policy determines the migration parameters for the storage class ac ross all storage
subsystems. Storage subsystem specific migration policies may be added which override the basic policy
in the selected subsystems. The storage subsystem specific migration policies share the migration Policy
ID and Policy Name with the basic policy.
6.4.1. Migration Policies Window
This window displays a list of all the configured migration policies.
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