Hi,

We have been pondering the problem of how to cope with network failure
within a network shared by many clients and one central database server.

Currently, clients queue updates when the network is offline, but in this
situation they then don't have access to it for queries, etc. The server is
also a single point of failure; rather bad news for all the clients should
it go down.

With advances in storage technology, it is becoming feasible to replicate
databases across all clients (at least, for the size of databases we have in
mind). The thought being some kind of peer-to-peer technology (the likes of
BitTorrent or Gnutella) could be employed to ensure all clients remain up to
date while the network is up. When connectivity returns, clients communicate
with each other to ensure their databases are synchronised.

Is this just a pipe-dream I'm having or do any products exist that could do
this?

(Current platform is Windows XP; I don't know whether that's relevant?)

Thanks for any help.

--
Regards,
Steve

"...which means he created the heaven and the earth... in the DARK! How good
is that?"

"Steve" <root (AT) 127 (DOT) 0.0.1> wrote

You can do this with the native database technology that the database
provides. (assuming the database provides it) (Just copying the datafiles
is a whole problem in itself, usually the database is writing to the
database while you are trying to send it somewhere. Won't work) You need
to make some decisions. How are you going to deal with stale data? How are
you going to deal with colissions? What is the worst impact to your
buisness if a client has the wrong answer because of stale data? Would
someone die? Would it be a minor inconvienience? Maybe it would be a
better idea to make the network more reliable.
Jim

Steve wrote:

Works quite robust.

--
Bernhard Brueck
(news (AT) brueck (DOT) muc.de)

Steve wrote:
There are really two issues here: 1) the RDBMS and the
application programs and 2) the data and its metadata.

Your real problem appears to be that your network isn't reliable
enough for your needs. If that is the case storage technology
cannot solve your problem.

Yes you can replicate your database, but be prepared for a
significant increase in network traffic, performance hits during
peak periods, an increase in the number of DBAs required to take
care of your increased number of databases and assure that they
really are in synch.

There is an inexpensive solution that may work. If you create a
backup once a day, export it to each client site and restore the
client database from the central facility backup your clients
can run against the central facility when it is available and
when it isn't queue their updates to run against the central
facility when it becomes available and run queries against the
local database.

In any event you would be better served by increasing the
reliability of your network.
HTH

Jerry Gitomer