> 1) What if the network between computer center and building A is
> disconnected ? I know that as far as two of the three database servers can
> communicate each other, there could be the 'sync site' and users can login.
> in computer center and building B. But I wonder what happens to the users
> in the building A. Can they login with the information of the database
> server in building A or not ? The admin manual says that the database server
> which can't get majority votes does not provide DB info to clients. Is it
> true ? All the clients in building A want to do is to read the DB info,
> not to change them.
Unfortunately, much of the documentation is out of date. It is possible
for a database server that can't talk to the sync site to server data
anyway, but in a read-only fashion. The real difficulty here is the
ptserver, which was the last server to support this capability. That
might have made it in by 3.3a, but might require 3.4; I can't remember,
but maybe someone else on this list can. If the 3.3a ptserver can't
do what you need, I'd reccommend upgrading your ptservers to 3.4a before
moving the machines.
> 2) Let's consider about clients. The manual says that client machine
> chooses the database server *randomly* when it boots up. If so, can the
> client switch to the new database server when the original database server
> can not provide informations no longer due to some reasons; network outages,
> server process crashes, etc... ?
Yes; that's the main point to having multiple database servers. Any
given client will pick some order to try servers in for each database
service, and if one fails, it will fail over to the next. Note that
this is independant for each database, so if one machine's ptserver
dies and a different machine's vlserver dies, you can still get info
and make updates.
-- Jeffrey T. Hutzelman (N3NHS) <[EMAIL PROTECTED]>
Systems Programmer, CMU SCS Research Facility
Please send requests and problem reports to [EMAIL PROTECTED]
