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Michael_E_Brown@xxxxxxxx wrote:
>
> Wensong,
>
> I agree, but... :-)
>
> 1) You can configure most mail programs to start refusing connections when
> load rises above a certain limit. The protocol itself has built-in
> redundancy and error-recovery. Connections will automatically fail-over to
> the secondary server when the primary refuses connections. Mail will
> _automatically_ spool on the sender's side if the server experiences
> temporary outage.
>
> 2) Mail service is a special case. The protocol/RFC itself specified
> application-level load balancing, no extra software required.
>
> 3) Central load balancer adds complexity/layers that can fail.
>
> I maintain that mail serving (smtp only, pop/imap is another case entirely)
> is a special case that does not need the extra complexity of LVS. Basic
> Queuing theory aside, the protocol itself specifies load-balancing,
> failover, and error-recovery which has been proven with years of real-world
> use.
>
> LVS is great for protocols that do not have the built-in protocol-level
> load-balancing and error recovery that SMTP inherently has (HTTP being a
> great example). All I am saying is use the right tool for the job.
I'd agree with all of the above. KISS, and in this case LVS is adds a
layer of complexity as Michael points out.
Greg
>
> --
> Michael Brown
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