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
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