Appendix D Accounting Examples
HPSS Installation Guide September 2002 495
Release 4.5, Revision 2
Whatkind of reports will be needed for your site? Learning what kind of accounting reports your
site will need to generate will help you determine how detailed the collected accounting
informationshould be. A typical Account Map will allow reports to be generated for the following:
• Total file accesses, amount of data transferred, and total space used per account, per class
of service, per storage class.
• Total file accesses, amount of data transferred, and total space used per user, per class of
service, per storage class.
D.8 Accounting Intervals and Charges
How often should HPSS accounting be run? How much should be charged for each unit of data
transferredand each unit of space used? The time between accounting runs and the charging policy
for space usage should be developed after consulting with the site accounting department. The
following are some guidelines to consider:
• Accounting should be run at a regular intervals, such as once per month.
• An accounting run may take several minutes, and the storage system will probably be
active during the run. The resource usage reported for each user will reflect the resources
used by that user at the point when the accounting run encounters that user. This is why
accounting represents a blurred snapshot instead of a snapshot at a single point in time.
• Certain accounting information is kept in cache for several minutes after it has changed.
Forthis reason, changes to a user’s accounting data may not appear in an accounting report
untilthis several-minute period has elapsed. Those changes which are still in cache when
accounting runs will not appear on the current accounting report, but will appear on the
next accounting report.
• The number of file accesses and the amount of data transferred can be taken to represent
the activity level of a certain user account in the HPSS system. You may wish to charge
specifically for the network and server resources consumed by this activity.
• Itmay be useful to charge different rates for each Class of Service. For example, a Class of
Servicethat keeps two tape copies of each file will use up more tape cartridges than a Class
of Service that keeps only a single copy of each file on tape.