Re: Indirect Synchronisation Setup
- From: jo <jo_young@xxxxxxxxxxxx>
- Date: Sat, 1 Nov 2008 07:18:00 -0700 (PDT)
On Oct 31, 9:11 pm, "David W. Fenton" <XXXuse...@xxxxxxxxxxxxxxxxxxx>
wrote:
jo <jo_yo...@xxxxxxxxxxxx> wrote innews:6a3f5b6d-bbe6-41f8-b8e0-91bcfd213d51@xxxxxxxxxxxxxxxxxxxxxxxxxxx
m:
I'm pretty new to replication and synchronisation. Having read
from a lot of sites about it, I think indirect synchronisation
(using TSI Synchroniser) is the method I need to use for the
particular situation I'm working with.
The situation is this. My client has an office with several staff
working over a network. The program in question is written in VB6
and uses a networked Access 2003 database. A few staff work from
home intermittently using their laptops. Currently they have to
key in retrospective data when they return to the office. An
automated synchronisation of local and remote databases would
remove this requirement, particularly as one staff member as a VPN
connection from home.
First off, you need to decide if the laptop user needs indirect
synchronization. I'd say that if the laptop is carried into the
office and connected to the office LAN, then you don't need any
indirect synch -- you can simply synch direct (because it's a safe
connection, i.e., over the LAN).
If you have users editing on their home computers (i.e., desktops,
not laptops), then you'd need to synch the data in and out, and for
that you'd definitely need indirect replication over your VPN.
I feel the first thing I should do is work out how to setup of all
the different components used in replication and synchronisation
and that is where I have already become unstuck! I wonder if
somebody might confirm whether my understanding is correct?
On the office server I should have a hidden folder for the Design
Master mdb,
There's no reason it has to be a hidden folder, but it should be
somewhere safe. In general, I don't put the DM in a share that users
have permission to use. A key point: the DM should not be used for
editing or for regular synching -- it's entire purpose is to be the
one replica where you can make design changes and you should use it
*only* for that (and synch it with the other replicas only when a
design change needs to be propagated, and often enough to keep the
DM from expiring. Given that the default retention period is 1000
days, a once-a-month synch should be fine).
it should have a related shared dropbox folder.
I would say the DM's location is not part of the indirect synch
topology -- it's only a resource necessary for maintaining the
replica set, but has no role in regular synchronization.
Also on
the server should be a production replica mdb, shared so as to be
visible to the office users. This should also have a related
shared dropbox folder.
No machine can have more than one synchronizer or more than one
dropbox. Since both your DM and your production replica are on the
same server, you'd have a single dropbox, since you have but the one
synchronizer. In short, back to the DM question, a DM has no need
whatsoever for a dropbox, since it's not going to be synched
indirect (if you want to propagate design changes, you synch with
the production replica, or with your synchronization hub, and those
replicas will then propagate the changes to the rest of the replica
set).
On a separate networked pc I should have the
replication hub mdb in an unshared folder.
Why on a different PC? I don't see why you shouldn't put your
replication hub on the same server as the production replica.
It should have a related
shared dropbox folder. The remote laptops should be set up each
to have a local replica mdb, invisible to the network.
If you're using something other than the server as your replication
hub, then you need no dropboxes at all on the server, since your
replication hub (which is on the same LAN, I assume) can synch
directly with the production replica.
It should have a
related shared dropbox folder that is visible to the network when
connected.
Every PC/server on which you have one or more replicas that you want
to synch indirectly needs to have a synchronizer with its own
dropbox.
The server should have Synchroniser continually running, similarly
the replication hub pc.
I would disagree strongly. The synchronization hub is on the same
LAN as the server, so you have no need to use indirect
synchronization. Thus, you don't need the synchronizer running on
the server at all.
Synchroniser should be installed on all networked
pcs and the laptops.
Well, only the ones that are going to be carried outside of the
office and need to be synched indirectly over the VPN while outside
the office. Any machine that is in the office and connected to the
LAN (whether all the time or only part of the time) has no need for
indirect replication and no need for the synchronizer to be
installed on it.
Is this a correct understanding of how indirect synchronisation
should be setup?
I would say you should have a much simpler replication topology:
1. keep the synch hub on the server.
2. don't synch indirect except when outside the office. That will
tell you which machines need to have the synchronizer installed.
Is it necessary to have a separate pc for the replication
hub?
No. The only reason many people do that is because they don't have
permission to run the synchronizer on the server 100% of the time
(which usually requires a locked user logon, something that's now
very easy with Terminal Server support on all Windows Servers).
Could the replication hub be on the server?
Absolutely, and that would be preferable, in my opinion.
If you fold the two functions into one server, keep in mind that you
will manage *only* the synchronization hub. You can set up a regular
synch schedule between the managed replica(s) and the production
replica without needing to manage the production replica.
Any pointers in the right direction would be much appreciated.
Let me know if what I've responded above helps. The key takeaway
ought to be, I think, that you don't want to get involved with the
administrative overhead of implementing indirect replication (and
installing the synchronizer and making sure it's running and all
that) except for the PCs that are going to be synched with the
mother ship over the VPN from outside the office. Any machine that
connects to the office LAN can use the much simpler direct
replication.
--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/
David,
Thank you very much for your response and for taking the time to
respond so thoroughly.
What you say makes good sense. It's refreshing when the solution is
more straightforward than previously expected! No doubt answers
always prompt more questions but meantime I have plenty to work on.
Thanks again.
.
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