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On Wed, 2007-02-21 at 09:41 -0600, Matthew wrote:
> It seems almost random. Here in our office, we have one DSL connection
> and all our desktop computers experience this behavior. From my house,
> Cable, no issues. From a friend in another city, no issues. From a
> customer in Chicago, issues present. ping's and traceroutes to/from all
> machines (including DIR and RS) are super fast.
I'm going to stretch a point here and suggest that this is down to PMTU
discovery and/or your clamping of the MSS on the realservers.
If the client does a PMTU discover on the VIP, then the answer is likely
to come from the director and be munged by intervening routers. They
might, quite happily, tune the MTU/MSS down to something like 400 bytes
(assuming there's a Frame Relay or ATM circuit somewhere in the path).
The realservers are happily then pumping 1440 at the clients, and the
intervening network is having to fragment like crazy and reassemble.
What happens if you do some MSS tuning to smaller sizes (or at the very
least, both the same) on both the director *and* realserver's outside
interfaces? Having them same, and not having them available to
auto-adjust, might well remove the problem for the clients with the
relevant network in between.
For the record:
>From home (4 Mbps cable) I fetch the image at about 10 KB/s
>From work (lots of Gbps) I fetch the image at about 282 KB/s
...so I can imagine the pain!
Graeme
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