05-2005 lb-l: RE: [load balancing] Re: nodes causing lag

From: Barrett, John <John.BarrettIZZATFMR.COM>
Date: Tue May 03 2005 - 09:16:26 EDT

Did you try other load balancing methods? (observed member, round robin
or ratio) It would be interesting to know if it seems to be happening
with other methods or not. I am getting ready to test the 6400 myself.
I have a 5000 with a couple of pools with 250 addresses in them and I
don't see any noticeable lag. No rules? What port (443 or 80)? Curious
about your setup.

-John Barrett

-----Original Message-----
From: Chuck [mailto:vegan-lb@wancom.com]
Sent: Tuesday, May 03, 2005 7:34 AM
To: lb-l@vegan.net
Subject: [load balancing] Re: nodes causing lag

When I tested with a single node vs multiple nodes I used the same #
users/bw/load/etc. This was a limited test where this was possible.

> Doing some testing this weekend on a new 6400 (9.05) we saw some
> application delays (about 400-500 ms). Have a plain vanilla VIP with
> about 45 nodes (least connections member, no persistence, not
> mirroring, etc). Doing a pretty low BW/low user test I saw the delay
> (600 users 10Mbits). I dont think this is unique to the 6400 - we
> previously ran on 5100 - we have basically always seen this lag in
our
> application - now we think we may know where it came from.
>
> Changed setup to use just one node and the delay went away (under
same
> user/BW load). Through trial and error saw that as the # nodes
> increased, my delay increased. Jumped through numerous hoops -
plugged
> nodes into BIGIP switch, used primary then secondary cat, added
virutal
> interfaces, added ports, removed ports, had all nodes on one box,
> spread all nodes to 12 different boxes, went through fw, removed fw,
> turned off ssl, etc, etc ... In each permutation always the same -
the
> more nodes - the more delay.
>
> Anyone have any thoughts on this? In my wildest imagination (and let
> me tell you it gets pretty wild) I cant imagine that simple LB to 45
> nodes introduces ANY latency - and especially not the 400 ms I am
> seeing. However - every test I have done points to that being the
> culprit.
>
> Open to suggestions for further tests, alternative conclusions, etc -
> would like to hear about anyone elses experience with pool-size, etc
>
> Not sure this matters - but our setup is RMI, with WebLogic
>
>
>

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