Some questions about replication

[andersonm82]

Allrighty, some questions about replication. I have gotten the Replication Manager from the helpful IT folks here, have made the database, and it works well to synchronise between different files locally on this computer. However, ideally the other people in the department would be able to carry replicas around on their laptops, while ideally the design master and overall database tidying should sit on mine. The setup is typical intranet here - computers are invisible to one another directly, and so are their virtual My Documents drives, while shared network folders are visible to all.

Questions;

1. Since I can't see any of the other laptop drives, and the database would have to be accessible offline, I assume indirect synchronisation is the only choice, correct?

2. Does the Replication Manager need to be installed on each of the laptops that will use the database offline?

3. If yes, what's the process? Do I install RM on each laptop, then use the Create Replica function to create one locally on each? No hidden pitfalls here?

4. If yes, is it sufficient to keep RM shut all the time unless specifically wanting to synchronise? Would happen at least once a week.

5. If Replication Manager doesn't need to be installed on other laptops, how do I move replicas there? I tried moving one through copy/paste, but that broke the link to the Replication Manager.

6. (Optionally - I've seen some references to 'replica farms' - what is that?)

Very much appreciated if anyone is able to answer..

 

[boblarson]

I've used replication and MS Replication Manager, so I'll try to answer your questions:

Questions;

1. Since I can't see any of the other laptop drives, and the database would have to be accessible offline, I assume indirect synchronisation is the only choice, correct? I would put the main database in a network folder and install Replication Manager to a server.

2. Does the Replication Manager need to be installed on each of the laptops that will use the database offline? No, one installation is necessary and it must be accessible to the replicas, so a network server is the best location. We had to do it on my machine (as they wouldn't let me install to a server) and so the synchs would happen only if my computer was on) as it handles the replication synchs between databases.

3. If yes, what's the process? Do I install RM on each laptop, then use the Create Replica function to create one locally on each? No hidden pitfalls here? You open RM on the server and create the replica to the laptop.

4. If yes, is it sufficient to keep RM shut all the time unless specifically wanting to synchronise? Would happen at least once a week. You can set up a replication schedule in RM so it will synch when you want and if the laptop is not connected it doesn't matter as that one will just be bypassed.

5. If Replication Manager doesn't need to be installed on other laptops, how do I move replicas there? I tried moving one through copy/paste, but that broke the link to the Replication Manager. You create a replica by logging into RM and you have to originally for the first one select Manage Database and then you can create a replica from RM to the locations you choose.

6. (Optionally - I've seen some references to 'replica farms' - what is that?) Don't know and can't speak to this.

 

[andersonm82]

Thanks for the replies - however I'm not sure if they will allow it to be installed on a server - this is a departmental thing somewhat isolated from IT. I've just dropped them a mail and asked - however alternatively, is it a possible setup to run the Replication Manager on each machine only running the programme when synchronising? Would then each of them work independently of one another, looking at the master replica and their own replica as a 2-replica set, each one set up to 'manage the set'? Would that lead to any problems or collisions?

I'm just concerned that, if it's not running on a server at the moment, then I could possibly get some help from IT to set it up, however I would probably not have access to the server on a day to day basis to clear any conflicts or problems, and I'm not sure if IT would like to spend the time doing it either for something not officially supported.

 

[boblarson]

I don't know how things would work if you install Replication Manager on each computer. I was under the impression that there should only be ONE replication manager instance, but I could be wrong (it's been known to happen ). You can try it out and see if it will work.

 

[dfenton]

1. Since I can't see any of the other laptop drives, and the database would have to be accessible offline, I assume indirect synchronisation is the only choice, correct?

I would put the main database in a network folder and install Replication Manager to a server.

Yes, it makes sense to put the data that needs to be seen by everyone on a network share. I would store the Design Master there, too, just not in a location easily accessible to your end users.

2. Does the Replication Manager need to be installed on each of the laptops that will use the database offline?

No, one installation is necessary and it must be accessible to the replicas, so a network server is the best location. We had to do it on my machine (as they wouldn't let me install to a server) and so the synchs would happen only if my computer was on) as it handles the replication synchs between databases.

Replication Manager doesn't need to be installed anywhere at all. It is a really sucky tool to begin with. Here are instructions on how to set up indirect replication without ReplMan:

http://groups.google.com/group/microsoft.public.access.replication/msg/3b7167c1462b2d2f

Another individual's take on the same thing:

http://www.vsj.co.uk/articles/display.asp?id=560

ReplMan can be helpful in learning to understand how replication works, though. If you're going to use it, you really only need it on the server, or on the workstation you're going to use to run the synchronizer that manages the replica that's on the server.

But it doesn't have to be installed on the laptops. Of course, many people have trouble getting indirect replication to work if they don't install ReplMan.

On the other hand, I'm having some difficulty understanding why you need indirect replication at all if you have a server where you can place a LAN-accessible replica that can be synched with by all the laptop users.

3. If yes, what's the process? Do I install RM on each laptop, then use the Create Replica function to create one locally on each? No hidden pitfalls here?

You open RM on the server and create the replica to the laptop

You don't have to use ReplMan to make the replicas. You don't have to use Access, either. Since you're just initializing the setup on the laptops, you can simply copy your hub replica off the server to the laptops. However, don't do this until *after* you've already configured the indirect synch hub on the server.

4. If yes, is it sufficient to keep RM shut all the time unless specifically wanting to synchronise? Would happen at least once a week.

You can set up a replication schedule in RM so it will synch when you want and if the laptop is not connected it doesn't matter as that one will just be bypassed.

ReplMan has *nothing* to do with running indirect synch. It's simply a UI to do it. The synch is actually performed by the synchronizer, and if the synchronizers on both ends of the synch are already running, you can initiate the indirect synch from the Access UI (as well as from code if you're using JRO; unfortunately DAO doesn't offer the ability to initiate an indirect synch, only direct and Internet).

5. If Replication Manager doesn't need to be installed on other laptops, how do I move replicas there? I tried moving one through copy/paste, but that broke the link to the Replication Manager.

You create a replica by logging into RM and you have to originally for the first one select Manage Database and then you can create a replica from RM to the locations you choose.

No, just copy the replicas to the laptops. There is need to create them in one place and then move them with ReplMan. You can just copy the hub replica with Windows Explorer, and it will assign a new ReplicaID as soon as you initiate a synch back with the hub replica.

6. (Optionally - I've seen some references to 'replica farms' - what is that?)

Don't know and can't speak to this.

A replica farm is a way to make indirect replication more robust. The concept was developed by Michael Kaplan, and is explained here:

http://trigeminal.com/usenet/usenet006.asp?1033

It would be wise of you to review all the replication-related articles on that website, as Michael Kaplan was once *the* genius on replication -- who has forgotten more than I and any 10 other Access developers know about replication.

--
David W. Fenton
David Fenton Associates
http://dfenton.com/DFA/