Funding Cyrus High Availability

David Carter dpc22 at
Mon Sep 20 06:21:58 EDT 2004

On Sun, 19 Sep 2004, David Lang wrote:

> assiming that the simplest method would cost ~$3000 to code I would make a 
> wild guess that the ballpark figures would be
> 1. active/passive without automatic failover $3k
> 2. active/passive with automatic failover (limited to two nodes or withing a 
> murder cluster) $4k
> 3. active/passive with updates pushed to the master $5k
> 4. #3 with auto failover (failover not limited to two nodes or a single 
> murder cluster) $7k
> 5. active/active (limited to a single geographic location) $10k
> 6. active/active/active (no limits) $30k
> in addition to automaticly re-merge things after a split-brin has happened 
> would probably be another $5k

I think that you are missing a zero (or at least a fairly substantial 
multipler!) from 5. 1 -> 4 can be done without substantial changes to the 
Cyrus core code, and Ken would be able to use my code as a reference 
implementation, even if he wanted to recode everything from scratch. 5 and 
6 would require a much more substantial redesign and I suspect quite a lot 
of trial and error as this is unexplored territory for IMAP servers.

David Carter                             Email: David.Carter at
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