Windows Server

Karl Frank · Guest

We have an insurance company. We use an application called Prime. Prime is
basically a database.

We have two servers. We can't afford to be down. One server is basically a
backup for the other and are identical as far as hardware is concerned.

We may have as many as 10 users in our company database at one time.
Obviously as those 10 people are talking to different customers and entering
information, the database is constantly changing.

How does or does DFS and RFS work with this. If server one crashes, can
server 2 pick up where we left off and not lose any data?

If you can't replicate the database in real-time, can you schedule
replication nightly and at the very least just possibly lose one days data?

Can you force users to always use the database file from server 1?

If server 1 goes down, server 2 kicks in, users access database from server
2. When server 1 comes back up, does it find changes with server 2 and
replicate without initiating anything manually?

If five users access a database from server 1 and five users access a
database from server 2, when the server replicates at night (assuming I am
only replicating once a day) do the changes merge or does one just overwrite
the other?

MOST IMPORTANTLY

If DFS and FRS is not a good solution for my fault tolerance needs, what is?

Thank you so very much in advance

Dan Lovinger [MSFT] · Guest

The latest changes always overwrite the older. The replication is of the
entire file - merging would require specific knowledge of the structure of
data in the file, how to identify differences, and is not generally part of
file replication products/tools.

You've done a great job of identifying the problems that could exist. The
1->2->1 transition is exactly what will break you, because users could keep
writing to 2 while new users are writing to 1. Then the last update wins
(repeatedly).

Unfortunately DFS and FRS are not going to be what you want, unless you can
afford to make a lot of compromises in terms of reliability and durability
of changes, and those are exactly the concerns you have below. They're great
at what they do - replicating readonly data, or data that is reliably
changed only in one location at a time. This is not that situation.

In fact, if this is what you have to do in the end, I would much rather you
do this directly so you are completely aware of every action in the system
and not relying on behavior of DFS and FRS which may be unclear to you.

You want to back-end Prime with a database with replication support. These
really is no other safe option. Microsoft SQL Server is one such database.
It will give you durable, transacted, replicated updates.

--
Dan Lovinger
Microsoft Corporation
Please do not send e-mail directly to this alias. This alias is for
newsgroup purposes only.

"Karl Frank" <Karl Frank@discussions.microsoft.com> wrote in message
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