Ingres Net over WAN

Simon Coles  writes:

>We have a requirement to support approx. 200 OpenRoad clients split over 
>2 sites (approx 100 at each site).
>
>We are going to connect the sites with an IP-routed WAN connection.
>As far as I can see, we have two choices on how to support the clients:
>
>a) have a single db server and support 100 of the clients over the WAN
>   connection.
>
>b) have a server at each site (the clients get local access) and use
>   Replicator to keep the servers in sync.
>
>The FAQ says that its a bad idea to run IngresNet over a WAN connection.
>Both a) and b) use NET (I think).  My *guess* is that b) is the best 
>option.
>
>Advice from anyone who has done this one way or the other would be 
>greatly appreciated.
>
>If this is all discussed in the manuals, please excuse me for wasting 
>your time (we haven't bought the product yet).
>
>TIA,
>
>Simon Coles                               Tel: (+44) 161 495 3040
>eurotao1.szhz3r@eds.com                   Fax: (+44) 161 428 5009
>
>

1) You are NOT wasting our time.  This is a great question.
   It's posted in the correct newsgroup.  It has everything to
   do with Ingres.  This kind of stuff is NEVER in manuals, and
   all salesdroids will say is "It works GREAT!"

2) I played with Ingres/NET over a WAN, but never ran it in 24 hour 
   production.  It seemed a bit sluggish, but fine.  I used TCP/IP
   (over the Internet).  Spank me, I'm bad.

3) You never characterized your WAN.  Is it a company WAN implemented
   via Frame Relay over fiber with backup satellite feeds, or just
   two 1200 baud modems between Greenland and Gilligan's Isle using
   cell phones.  Good WANs are VERY reliable, and sometimes very fast.
   Is the WAN city-wide, nation-wide, planet-wide?

   You can test you WAN's reliability by writing a simple echo client
   and server (with timestamps) and running it for two weeks.  If you
   see good response and no "dead times" after two weeks, you are
   probably working with a good WAN.  Simple, but statistically sig-
   nificant.

   Make sure you speak with your WAN people, so they can plan for 
   the increased traffic you plan to impose.

4) What transaction volume do you expect?  Are this simple-keyed lookups
   or full-motion video downloads.

5) Both your solutions need Ingres/NET.  Ingres/NET (6.4) does not handle
   broken networks well, but the new versions in OpenIngres 1.1 supposedly
   do.

6) If the data is regional, and only updated by users in the region, 
   you might consider manual horizontal partitioning.  Rolling your
   own isn't easy, but it might work better.

7) If the data is randomly updated by randomly located users and 
   synchronization is critical, you might consider using Ingres/Star
   or a TP monitor like Encina/Tuxedo/CICS.  However, this is 
   NOT trivial.  Ask any computer manufacturer about air-line 
   reservation systems.  They all wince.

Hope this helps,

Cheers,

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