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Old 2nd Jun 2017, 10:36
  #459 (permalink)  
Nialler
 
Join Date: May 2008
Location: Paris
Age: 56
Posts: 101
You know those films where it takes forever to kill the baddie? Those films where he (or she) keeps coming back despite apparently having been killed? That's what a GDSP (geographically dispersed sysplex) is like.


Yeah, I know that any mainframers reading this will nod knowingly. In one sense it's easy to bring down a system. However, when you have multiple hot swaps available, so long as they are fit for purpose the requirement is to take all of them down first - to cut the links from the running system to them, and, if properly configured, to take them down rather than have them polling the active primary and swinging into action if there is no response. So, You get onto all of those, issue a "z eod" command, wait until they are all down before "eod"ing the active system.


45 minutes to an hour of activity, all of which is creating a huge amount of alerts. Think flashing lights and sirens. If I tried to take down such a system I'd expect to be stopped within five minutes. OK, I can take an axe to my primary system in France, but even with the TGV it is a bit of a haul to the secondary site in Luxembourg, and I might need a confederate in Brussels. They'll need an axe and access to the datacenter.


That is a description of resilience.
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