[Cialug] Troubleshooting high latency/low speed

Nathan C. Smith nathan.smith at ipmvs.com
Mon Jul 26 16:59:57 CDT 2010


not sure what you actually have access to, but duplex mismatches and strange routing come to mind.  Does the route always come back the same?  an MTU mismatch might also cause latency in some things but not in others.  you could try pinging with successively smaller packet sizes to see which ones go through best.   Not an expert with this but one of them will chime in soon I'm sure.


-Nate



________________________________
From: cialug-bounces at cialug.org [mailto:cialug-bounces at cialug.org] On Behalf Of Matthew Nuzum
Sent: Monday, July 26, 2010 4:46 PM
To: Central Iowa Linux Users Group
Subject: [Cialug] Troubleshooting high latency/low speed

Hello, I've got a server and accessing it is slow lately (about a week now). Sometimes just slow, other times intolerably slow.

Ping does not indicate too much prob. Latency is about 70-80ms which is fine. However SSH, HTTP and even HTTPS over a non-standard port all make it clear there is a problem. Can you suggest how to troubleshoot this?

wget http://www.bearfruit.org/wp-includes/js/jquery/jquery.js
100%[===========================================>] 72,194      7.59K/s   in 9.3s

2010-07-26 16:35:53 (7.59 KB/s) - `jquery.js' saved [72194/72194]

(NOTE that it took 9.3s to download a .js file)

Also, traceroute shows high latency when I test the server, but my brother tested from ISU and he also noticed the slow speed and he's on ISU's campus (not mediacom):

traceroute to www.bearfruit.org<http://www.bearfruit.org> (69.60.125.106), 30 hops max, 60 byte packets
 1  buffalo.setup (192.168.1.1)  4.140 ms  7.958 ms  8.432 ms
 2  10.19.76.1 (10.19.76.1)  16.084 ms  19.137 ms  19.232 ms
 3  172.30.1.81 (172.30.1.81)  29.518 ms  29.621 ms  29.720 ms
 4  172.30.1.53 (172.30.1.53)  27.287 ms  29.260 ms  28.953 ms
 5  12-215-4-22.client.mchsi.com<http://12-215-4-22.client.mchsi.com> (12.215.4.22)  30.601 ms  229.057 ms  229.443 ms
 6  cr84.cgcil.ip.att.net<http://cr84.cgcil.ip.att.net> (12.122.132.98)  231.008 ms  206.822 ms  332.461 ms
 7  cr2.cgcil.ip.att.net<http://cr2.cgcil.ip.att.net> (12.123.7.250)  332.542 ms  332.699 ms  332.850 ms
 8  cr1.n54ny.ip.att.net<http://cr1.n54ny.ip.att.net> (12.122.1.1)  333.005 ms  203.557 ms  203.937 ms
 9  n54ny02jt.ip.att.net<http://n54ny02jt.ip.att.net> (12.122.80.225)  201.973 ms  205.819 ms  208.754 ms
10  192.205.37.134 (192.205.37.134)  208.838 ms 192.205.36.78 (192.205.36.78)  205.243 ms 192.205.37.134 (192.205.37.134)  208.864 ms
11  te0-2-0-4.ccr22.jfk02.atlas.cogentco.com<http://te0-2-0-4.ccr22.jfk02.atlas.cogentco.com> (154.54.1.217)  208.952 ms  209.012 ms te0-2-0-4.ccr21.jfk02.atlas.cogentco.com<http://te0-2-0-4.ccr21.jfk02.atlas.cogentco.com> (154.54.2.185)  430.110 ms
12  te0-0-0-2.ccr21.dca01.atlas.cogentco.com<http://te0-0-0-2.ccr21.dca01.atlas.cogentco.com> (154.54.25.238)  231.746 ms te0-1-0-7.ccr21.dca01.atlas.cogentco.com<http://te0-1-0-7.ccr21.dca01.atlas.cogentco.com> (154.54.26.6)  232.186 ms te0-2-0-7.ccr21.dca01.atlas.cogentco.com<http://te0-2-0-7.ccr21.dca01.atlas.cogentco.com> (154.54.41.1)  232.564 ms
13  te3-8.ccr02.atl01.atlas.cogentco.com<http://te3-8.ccr02.atl01.atlas.cogentco.com> (154.54.1.33)  232.975 ms te9-2.ccr01.atl01.atlas.cogentco.com<http://te9-2.ccr01.atl01.atlas.cogentco.com> (154.54.24.154)  233.059 ms te7-2.ccr01.atl01.atlas.cogentco.com<http://te7-2.ccr01.atl01.atlas.cogentco.com> (154.54.28.214)  227.670 ms
14  te3-4.ccr02.mia01.atlas.cogentco.com<http://te3-4.ccr02.mia01.atlas.cogentco.com> (154.54.3.26)  238.692 ms te3-1.ccr01.mia01.atlas.cogentco.com<http://te3-1.ccr01.mia01.atlas.cogentco.com> (154.54.30.34)  235.215 ms te3-1.ccr02.mia01.atlas.cogentco.com<http://te3-1.ccr02.mia01.atlas.cogentco.com> (154.54.26.10)  238.495 ms
15  vl3512.na21.b015452-0.mia01.atlas.cogentco.com<http://vl3512.na21.b015452-0.mia01.atlas.cogentco.com> (66.250.14.182)  235.593 ms  235.679 ms  236.002 ms
16  38.104.90.190 (38.104.90.190)  236.089 ms  237.478 ms  236.939 ms
17  233-160-111-65.serverpronto.com<http://233-160-111-65.serverpronto.com> (65.111.160.233)  237.884 ms  231.885 ms  228.001 ms
18  hosts.bearfruit.des-moines.ia.us<http://hosts.bearfruit.des-moines.ia.us> (69.60.125.106)  232.530 ms  232.364 ms  232.571 ms

--
Matthew Nuzum
newz2000 on freenode, skype, linkedin, identi.ca<http://identi.ca> and twitter

"Never stop learning" -Robert Nuzum (My dad)
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