[evlatests] Plans for old monitor data

[Bill Sahr]

Over the next week or so the ECD will be fielding a new monitor data
archive and a new query interface that works with that new monitor
data archive.  Once the new monitor data archive is created, it will
be filled with data from the test version of that archive, so it will
go online containing about 4 to 6 weeks worth of old monitor data.

The new monitor data archive will be known as evlamcdata.  The old
monitor data archive, the one that is being replaced, is known as
evlamon.  Evlamon has been with us for some time now.  It contains,
or is the means of access to, all EVLA monitor data that has been
collected upto this point in time.

The question I wish to pose is what should we do with do with this
old monitor data?

Our present plan is as follows:
   For a while, evlamon will continue to exist.  We will even continue
filling new monitor data to evlamon for one or two weeks after the new
monitor data archive comes into existence.  After that 1 or 2 week
period, we will stop filling monitor data to evlamon, but allow it
to continue to exist.  It will be accessible via the old monitor data
query interface.
   After a period of approximately 3 months from the time we stop filling
new monitor data to the old monitor data archive, we suggest that
1. the contents of evlamon be archived
2. the actual database, evlamon, be destroyed (i.e. no active, actual
    instance of it will exist), and
3. the old query interface disabled

It is important to understand that these steps will, without some 
considerable amount of effort that we would undertake only with
great reluctance, make monitor data predating the rollover to the new 
monitor data archive inaccessible.  Barring the mounting of that
"considerable effort" the old monitor data would cease to exist and
would no longer be accessible.

We (the M&C Group in the ECD) want comments on this plan.  If you
feel that the loss of basically all monitor data for the EVLA and
whatever VLA data may happen to be in the EVLA archive, upto a
point in time of approximately the end of May 2007 is unacceptable,
please speak up now.  Later will be too late.

Please be thoughtful about this matter.  If there really is a need to
keep this data and to keep it accessible, we will find a way to do so.
However, doing so will require effort, time, energy, money, and
resources.  If this data is not really needed, then let's not keep
it.  Please let us know what you think, either by a posting to
evla-sw-discuss or evlatest, or by direct email to me, bsahr at nrao.edu.

Thank you.

Bill Sahr