Multiple Location setup options
Hi,
I'm considering OpenVPMS for a multi-location practice. The obvious setup is server at one location, internet access from all the others (or server hosted at some rack-space provider), but I'm concerned that if they have any internet troubles (which does happen from time to time) the remote practices will be completely offline.
Is it possible/has anyone done it to set things up so that there is a database at each location which synchronizes in some way when online but can operate separated for some period. I realize this is a bit complicated, but any relevant experiences?
Thanks,
James
Multiple Location setup
I haven't heard of anyone doing this, but the obvious approach would be to use MySQL replication.
With standard replication, you would nominate one practice database the 'master',
and the other practice's databases 'slaves'.
The master database replicates updates to the slaves.
The disadvantage of this approach is that:
1. You can only perform updates to the master database, so if your network is down, you can't save changes
2. OpenVPMS doesn't support it. Currently OpenVPMS expects to read and update the same database.
You can get round this by using circular replication. Here, each database replicates to every other database.
One issue with this approach is that two practices can update the same data and cause a conflict.
Another potential limitation is described here: htp://dev.mysql.com/doc/refman/5.1/en/replication-faq.html#qandaitem-17-4-4-1-5
A good overview can be found here: htp://onlamp.com/pub/a/onlamp/2006/04/20/advanced-mysql-replication.html
(note change the links from htp to http - can't get them past drupal's spam filter otherwise)
-Tim
Multiple Location setup
Thanks, that's helpful. Basically it's very complicated and tricky and really would need to be coded in at the application layer. Oh well, that's no different to the commercial options available.
Thx,
James