Replicate to more than one replica?

[Roland Pope]

David Korpiewski wrote:
> Is it possible for one master to rolling replicate to more than one 
> replica?   I'd like to have one master and two replicas.  However, I 
> can't determine how to do this within the imapd.conf file.  I swear I 
> read that you can have more than one replica.  Can you let me know if 
> I'm mistaken?
>
> (1) sync_host: lmc1.cs.umass.edu lmc2.cs.umass.edu
>
> produces:
> Jun  6 13:36:15 lmc1 sync_client[7739]: getaddrinfo(lmc2.cs.umass.edu 
> lmc3.cs.umass.edu) failed: Name or service not known
> Jun  6 13:36:15 lmc1 sync_client[7739]: Could not connect to 
> lmc2.cs.umass.edu lmc3.cs.umass.edu (attempt 1 of 1 max)
>
>
> (2) sync_host: lmc2.cs.umass.edu
>     sync_host: lmc3.cs.umass.edu
>
> produces:
> Jun  6 13:39:33 lmc1 master[8619]: option 'sync_host' was specified 
> twice in config file (second occurance on line 30)
>
>
> (3) sync_host: lmc1.cs.umass.edu, lmc2.cs.umass.edu
>
> produces:
> Jun  6 13:37:48 lmc1 sync_client[8309]: 
> getaddrinfo(lmc2.cs.umass.edu,lmc3.cs.umass.edu) failed: Name or 
> service not known
> Jun  6 13:37:48 lmc1 sync_client[8309]: Could not connect to 
> lmc2.cs.umass.edu,lmc3.cs.umass.edu (attempt 1 of 1 max)
>
>
> Thanks for any help.
> David
>
>
You cannot replicate from one master to more than one replica.
However, you should be able to replicate from master to replica, then 
from replica to another replica.

Ie. Master->Replica1->Replica2

I realise this will introduce a small delay in the replication from 
Master to Replica2, and will rely on replica1 being available, but it 
should still be a valid option.

Cheers,
Roland