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On-line BACKUPs? Ensuring Data Consistency?

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The Question is:

 
We have recently had a Compaq Alphaserver DS20 installed together with a DLT
35/70 Tape Drive.
 
We have been informed by the company whose software resides on the Alpha
that if any users are logged in when the backup is due to take place, then
the operation will fail.
 
Is there a solution which will allow the backup to perform successfully,
similar to open file backup agents for Novell/NT. (The backup currently runs
at 3am)
 
We are trying to ensure that all users are logged out on an evening, but
because of the large userbase their may from time to time be a situation
where a system is left logged in or logged out incorrectly.

The Answer is :

 
  There are a variety of tools that can be used to detect and terminate
  logged-in users.  The general class of tools are called "idle process
  killers", and both commercial and freeware variations are available.
 
  Within the IPK, use of $forcex over $delprc is generally recommended as
  the initial process termination call.  These tools can potentially lead
  to corruptions in the target process, if the application caches data -- the
  situation is similar to the potential corruptions caused by a system crash.
  (The emphasis here is on the word POTENTIAL.  These corruptions are usually
  UNLIKELY -- most applications recover nicely from system crashes.)
 
  That said, a simple script using the output from SHOW DEVICE/FILES to spot
  processes with the application file(s) open.  (This command would be needed
  on each node in the OpenVMS Cluster.)
 
  Also inquire if the vendor has any plans for adding synchronization into the
  application -- Oracle Rdb provides tools that perform database backups, even
  with users logged in, via the RMU tool.  In conjunction with the BACKUP API
  and the OpenVMS distributed lock manager, applications can be extended to
  perform the necessary synchronization.
 
  OpenVMS Engineering is aware of the need for better on-line BACKUP operations,
  and is evaluating potential alternatives for incorporation into one or more
  future OpenVMS releases.
 


  

     
     
answer written or last revised on ( 20-SEP-1999 )

     
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