Re: High Speed Firewalls

[Bennett Todd <bet () rahul net>]

2000-03-03-08:52:40 Woeltje, Donald:
> Now, if I remember correctly, the Cisco solution was running
> in the low $20k's, almost price competitive with the Layer 4
> switches on the market (including Alteon, which was the only Layer
> 4 switching product I tested).  But in my mind there was just no
> comparison, overall. Why pay more for less when you can pay less
> for more?

As far as I know, the Cisco LocalDirector remains unique among load
balancers in the basic way it works.

It dispatches incoming requests to servers in the farm, and keeps
a notepad to make the assignments "sticky"; so far they're all the
same. But LocalDirector keeps track of how quickly each server in
the farm responds to a request, and always assigns the next new
connection to the server who responded fastest. This allows it to
automatically drop failed boxes out of the pool, and re-introduce
them when they're brought back (HA failover); again, all the
load balancers should be able to do that. But LocalDirector also
gracefully eases the load off boxes that are weaker, either because
they aren't all identically configured, or because a box sometimes
does some additional processing. E.g. if you need to sweep rsyncs
over your farm to update content, if anybody gets mashed against the
wall by the rsync plus their serving load, the LocalDirector will be
able to ease off the hurting boxes.

For some applications, namely similarly configured servers that
never do any significant extra processing, this feature may not pay
its freight. In which case yes, the LocalDirector isn't competitive.
But for a lot of jobs I still love it the best and specify it by
strong preference.

Are there any other load balancers out there that can keep
track of how fast their servers respond, and always prefer the
currently-fastest box?

-Bennett

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