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Conference csc32::consolemanager

Title:POLYCENTER Console Manager
Notice:Kits, Scans, Docs on CSC32:: as PCM$KITS:,PCM$DOCS:, PCM$SCANS:
Moderator:CSC32::BUTTERWORTH
Created:Thu Aug 06 1992
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1541
Total number of notes:6564

446.0. "Daylight Savings Time Strategy" by CSC32::C_TOWNSEND () Mon Oct 24 1994 00:58

    Hey again,
    
    Daylight savings time is coming next week, and already customers are 
    asking about the impact to PCM.  Could you recommend the appropriate
    strategy to manage this event so that PCM won't get crazy over
    duplicate time stamp or advanced system times?  Your information will
    provide the basis for a STARS database article available to customers
    for this painful twice-a-year event.
    
    Thanks,
    Connie
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446.1OPG::PHILIPAnd through the square window...Mon Oct 24 1994 10:2923
Connie,

  Good point,

  Logging of data will occur normally, its just that duplicate
  entries will be in the times files, this is legal and expected.

  Now, what is this going to affect?

  I dont beleive any of the interfaces really care about the
  timestamps in the log and archive files unless you need to
  specifically go for a time, such as "FIND TIME" within the
  Monitor interface. In this case you will be able to find
  the same time twice unless you are going for an absolute
  time, in which case I am not sure which one of the duplicates
  you will get!

  What are your customers specific concerns?

Cheers,
Phil
446.2Customer concernsCSC32::C_TOWNSENDMon Oct 24 1994 15:4528
Phil -
    
    Customer concerns are varied depending on their environment, however
    former VCS customers were advised via Release Notes as to the steps to
    avoid VCS rolling over when it encountered duplicate keys based on
    timestamps.

EXTRACT FROM DOCUMENT:    "VAXcluster Console System 1.4 Release Notes"

"VCS uses the VMS system time (in the system time 64-bit format) for time
stamping the received console data. That time stamp is also used as the
index key in the VCS RMS console and event log files. When a time change
occurs on the VCS host system (especially when Daylight Savings Time is set
in the Fall), the risk of duplicated keys exists during the overlapping
time period. This problem is inherent to the way VMS maintains the clock
time."   [The workaround follows this text.]
    
    Another concern for customers will be customized ENS actions that are
    dependent on EXTRACT data with checks against timestamps.  I personally
    know of number of customers doing some fancy checks.  Do you think an
    ARCHIVE or some other strategy might be used to avoid problems?  Could
    you do some testing so that we can say ...Engineering recommends blah?
    
    Thanks again,
    Connie
446.3OPG::PHILIPAnd through the square window...Mon Oct 24 1994 16:0020
Connie,

  The VCS statement is irrelevent for PCM as we dont use indexed
  files (or at least not RMS indexed ones!). All our files point
  to offsets within each other, we only use the time file to get
  the actual time of the line of log data. Events have their own
  timestamp within the event file.

  Extract will find the FIRST occurence of a particular time and
  work forwards from their, so if the ask for 00:15 onwards, they
  will possibly get an extract containing two 00:15 timestamps.

  I dont beleive archiving will help in the current version of the
  product as all that happens in a review is that several archive
  files are "appended" the resulting data is then what is reported
  against.

Cheers,
Phil
446.4Okay!CSC32::C_TOWNSENDTue Oct 25 1994 02:527
    Okay Phil -
    
    I'll put together a recommendation to 'just change time as needed' - 
    PCM is robust enough to manage the issue.  
    
    Thanks,
    Connie