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stormdrain
Asked: 2011-08-04 07:51:13 +0800 CST

QoS switch messing with local http traffic?

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WE just moved our rack to a datacenter in the building. In our rack is a blade running centos and apache for intranet stuff. When we moved to the DC, we essentially extended our LAN there via adding a cisco switch. Since moving there, our intra sites have become painfully slow.

Looking at a wireshark cap, my inexperienced eyes don't see anything that sticks out as the culprit, though it's easy to see where the delay is:

slow cap

20 seconds there on the TCP segment of reassembled PDU. And there are a lot of those that follow, but none with a delay like that. Most are ms in length.

The only thing I can think is that the switch we are using in the DC has QoS on it. That's really the only difference I can think of other than the physical location being about 300 feet further away.

Is this something QoS might do? If not, what may be some other culprits?

Thanks.

networking apache-2.2 latency

2 Answers

  1. Best Answer

    Severe performance problems on a LAN can caused by speed/duplex mismatch on an uplink. Can you confirm that this server and service is not the only one affected?

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  2. Used straight through cable instead of crossover cable as needed. Traffic was still getting through, but it was taking much longer as the timeout needed to occur before finding an alternate route.

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