Cyrus IMAP and MySQL mailboxes (Building load-balancing cluster)

[Marcelo Maraboli]

Hi.

thanks for the input, I know wishing 100% is only available
with a gooooogle size amount of money ;), but I am looking
for a CYRUS IMAP server solution similar to a load balancing
web server farm...i.e:

- a Load balancing server (PEN in Freebsd if you like) that
will direct an IMAP session to ANY of a group of IMAP servers,
all of which have access to a central storage of user MBOXs.

So if any of the IMAP (backend) server dies, the load balancer with
automatically not forward any new requests to that server
and users won´t notice any downtime..

this is diferent from Andrew´s solution number 1, since ANY of
the backend IMAP server should accept connections for ANY user.

examples:
http://siag.nu/pen/vrrpd-linux.shtml
http://redundancy.org/fbsd_lb.html

can IMAP be set up this way ??

regards,

Robert Banz wrote:
> 
> On Nov 20, 2006, at 06:34, Marcelo Maraboli wrote:
> 
>> Andrew
>>
>> thanks for the "scalable" Cyrus solutions, but I´m wondering
>> what can be done for Availability solutions ??
>>
>> What if an IMAP server dies (we had this happen) ??
>>
>> We have a Solaris Server with a RAID5 disk array storing the
>> MBOX, but the server died....so downtime was a bit huge..
>>
>> I wan to build a 100% available IMAP solution...is there any?
> 
> Even with a couple dumptrucks full of money, nobody could pull off 100%.
> 
> ...but you can get really close.
> 
> Consider housing your storage on *two* individual storage devices, 
> potentially in different buildings.  Mirror between them at the host 
> level (cheap), or, through multiple redundant storage virtualizers (pricey)
> 
> Set up an active/passive cluster.  Relatively "easy" to do nowadays.  Or 
> go the clustered FS route (but then you'd probably need the storage 
> virtualizers)
> 
> Basically, for each '9' after 99% uptime, expect to double your cost and 
> complexity of implementation.
> 
> -rob
> 
> 
>  

-- 
Marcelo Maraboli Rosselott
Jefe Area de Redes y Comunicaciones (Network & UNIX Systems Engineer)
Ingeniero Civil Electronico, CISSP       (Electronic Engineer, CISSP)

Direccion Central de Servicios Computacionales (DCSC)
Universidad Tecnica Federico Santa Maria        phone: +56 32 2654071
Chile.                 http://www.usm.cl   http://elqui.dcsc.utfsm.cl