HP OpenVMS Systems

UPS, Battery, Standby Power?

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The Question is:

 
Changes to data in file mapped global sections are lost upon power failure
 unless flushed implicitly by OpenVMS (as part of paging) or explicitly by the
 application. A better solution would be if OpenVMS could perform an automatic
 shutdown on power failur
e sustained by a little say 120 sec. internal battery. Does such a feature exist?
 
 

The Answer is :

 
  The basic approach with the global sections can unfortunately have
  some potential flaws, as one obvious potential exposure here is to
  system failures and to application failures -- or worse, to failures
  which can leave potentially corrupted data in the sections resulting
  from an aberant application failure.  Galactic memory is particularly
  vulnerable -- not because of the operation across multiple instances
  in an OpenVMS Galaxy configuration -- because it is the only type of
  global section that can typically survive even an OpenVMS system
  failure with its contents entirely intact.
 
  Put another way, this area is where available middleware and related
  approaches can provide benefit and value -- with the information written
  to static storage (eg: disk) and/or replicated across multiple servers
  (eg: Compaq RTR, or the Iona or BEA middleware offerings), your
  application can then restart.  And you don't have to write and
  maintain this code.
 
  Also please see existing discussions including topics (6960), (4487),
  (4051), (3791), (3635), (3365), (2486), (2637),  (2181), (860), and
  others -- these are discussions that can be relevent to correct
  operations of shared memory on OpenVMS.
 
  That said, the failure modes of the shared memory section can be
  seperated from the discussions of standby power, battery backup, and
  controlled shutdown.
 
  The OpenVMS Wizard is aware of no current Alpha systems that offer
  internally-integrated battery backup, this capability is assumed to
  be provided external to the system via UPS, motor generator, or similar.
  (In addition to the power requirements of the system, there are a large
  number of other supporting components of the local computing environment
  that can require standby power -- most notably, storage controllers,
  storage shelves, display consoles, and network hardware.)
 
  Please see the OpenVMS FAQ for pointers to information on available
  UPS control software.
 

  

     

     
answer written or last revised on ( 4-JAN-2002 )
     
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