RE: multiple squid with load balance

On Fri, 9 Jul 1999, Williams Jon wrote:

> 3) L4 switch-type - this is a device such as a Cisco LocalDirector or Alteon
> ACEDirector which sits between the main network and a farm of servers and
> redirects traffic across a group of similar services. This can provide both
> true load-balancing and high availability.
>
> I've just recently finished a paper on this for a class I was taking, and
> for availability and load distribution, I found that the third type had the
> most benefits. Furthermore, it makes scaling much easier, since you can
> simply add another box to the farm when you outgrow your current setup. The
> biggest drawback to it, though, is purchase price, since L4 switches aren't
> cheap, but if you're dealing with a large environment with high demand and
> little tolerance for down-time, it is the best way to go.

IMO, the biggest drawback of L4 switches at the moment is that they do
not work well, especially under high loads. We are seeing bizarre L4
bugs, misfeatures, and poor performance when benchmarking caches with
various L4 solutions. Hopefully, switch manufactures will catch up fast,
but one must take into account that L4 is not just a nice little
feature, but a different dimension/paradigm compared to L2, and switch
people need time to learn. Sort of like migrating from a calculator to a
computer...

Meanwhile I would recommend to test drive a L4 switch before taking it
into production (especially for high load environments).

$0.02,

Alex.
Received on Fri Jul 09 1999 - 09:34:25 MDT