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Re: Latency for some clients

To: "LinuxVirtualServer.org users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: Latency for some clients
From: Joseph Mack <mack.joseph@xxxxxxx>
Date: Tue, 25 Mar 2003 06:05:36 -0500
Per Wicklund wrote:

> Does anyone have a clue of what may cause the latency? Is there any easy way
> of measuring where the latency occurs?

The usual causes are 

o identd/authd
o routing problems within the LVS
o DNS lookups (which can be slow)

tcpdump is the usual tool. You'll need a client which
can reliably get the pause and then watch the director
and the realservers with tcpdump. You should try to figure
out ahead of time what is different about the clients
that are getting the high latency connections (put a machine
with a different OS at that IP, use a different client,
eg telnet instead of http)

Joe


-- 
Joseph Mack PhD, Senior Systems Engineer, SAIC contractor 
to the National Environmental Supercomputer Center, 
ph# 919-541-0007, RTP, NC, USA. mailto:mack.joseph@xxxxxxx
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