Rob,
Rob Siemborski wrote:
I hope this kind of functionality comes into cyrus once; I assume it is not there yet, I once asked this on the list before ;-) And maybe it shouldn't be too difficult, since there is already a synchronisation mechanism for NNTP in place, if I'm correct.
This is very hard -- if not impossible -- with only two machines, at the very least you'd need three in order to maintain a quorum of what the "real view" of the server is --
For example, think about what would happen if there was a network partition and two different messages were delivered to the split servers at the same time. It's not an easy problem to solve-- keeping a hot spare is definately the way to go.
I agree; but what I meant was a synchronisation mechanism that can synchronise a spool with/to a hot spare server - without having the need for a RAID unit with two scsi interfaces. (This way you remove another SPOF ;-))
Maybe I see this a bit like the OpenLDAP slave/master replication idea: something must "switch" in order to make the slave the master and vise versa. Cyrus could synchronise the slave with every message delivered, or when keeping a log and synchronising the messages apart.
Although I think Gerard likes to see both servers active at the same time, I think the (master-slave kind) synchronisation would be a nice thing to start with. On the other hand, if I see what offlineimap can do, I assume it must be possible with just 2 servers to synchronise folders in a proper way (when keeping some history and logs on both sides, of course...), am I wrong? (This looks again a bit like bi-directional synchronisation as with unison, instead of master->slave think as with rsync or so.)
Regards, Paul
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