From: Yehuda Bock
Subject: [IGSMAIL-0966] Long Weekend
Date: Wed, 31 May 1995 12:19:57 PDT

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IGS Electronic Mail      Wed May 31 12:19:57 PDT 1995      Message Number 0966
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Author: Yehuda Bock
Subject: Long Weekend

Scripps Orbit and Permanent Array Center (SOPAC)
Date: May 31, 1995

Re: Long Weekends

The downtime of the JPL computers this Memorial Day weekend
brings up some critical issues of backup and redundancy. We
were not able to obtain data from JPL between Saturday and
late Tuesday because of an air conditioning problem as posted
promptly on IGS mail.

It is clear from this down time that the JPL download
component is critical to the IGS.  Also, we depend on
JPL to download almost half of the SCIGN stations.     

Consider the following (not entirely unlikely) scenario in which there
is a major earthquake in the Los Angeles Basin and the JPL
facility goes off line.  The IGS orbit computation will
basically grind to a halt (for lack of data) which will degrade
the processing of the remaining downloaded SCIGN stations downloaded
by SOPAC.  Of course, any of the IGS centers could go down for
one reason or the other.

I'm not aware of any backup plan in effect (correct me if I 
am wrong).  The proper approach is to build into the system 
backup download capability.  That is, one center can back up
another in the event of an emergency. 

To start developing this backup plan, we propose to exchange
site download information with JPL so that we could backup
each other (globally & regionally) if the need arises.






[Mailed From: pgga@pgga.UCSD.EDU (Geodesy Lab account)]