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Re: Swift performance issues with requests
I found the problem. I placed a hardware balancer in front of the proxy server.
The balancer lost some packets because of a faulty network interface.
Your tip was excellent.
Von: Rick Jones [mailto:rick.jones2@xxxxxx]
Gesendet: Freitag, 31. Mai 2013 19:17
An: Klaus Schürmann
Betreff: Re: [Openstack] Swift performance issues with requests
On 05/31/2013 04:55 AM, Klaus Schürmann wrote:
> May 31 10:33:08 swift-proxy1 proxy-logging 10.4.2.99 10.4.2.99 31/May/2013/08/33/08 GET /v1/AUTH_provider1/129450/829188397.31 HTTP/1.0 200 - Wget/1.12%20%28linux-gnu%29 provider1%2CAUTH_tke6408efec4b2439091fb6f4e75911602 - 283354 - txd4a3a4bf3f384936a0bc14dbffddd275 - 0.1020 -
> May 31 10:33:26 swift-proxy1 proxy-logging 10.4.2.99 10.4.2.99 31/May/2013/08/33/26 GET /v1/AUTH_provider1/129450/829188397.31 HTTP/1.0 200 - Wget/1.12%20%28linux-gnu%29 provider1%2CAUTH_tke6408efec4b2439091fb6f4e75911602 - 283354 - txd8c6b34b8e41460bb2c5f3f4b6def0ef - 17.7330 - <<<<<<<<<<<<<<
Something I forgot to mention, which was the basis for my TCP
retransmissions guess. Depending on your kernel revision, the initial
TCP retransmission timeout is 3 seconds, and it will double each time -
eg 3, 6, 12. As it happens, the cumulative time for that is 17
seconds... So, the 17 seconds and change would be consistent with a
transient problem in establishing a TCP connection. Of course, it could
just be a coincidence.
Later kernels - I forget where in the 3.X stream exactly - have the
initial retransmission timeout of 1 second. In that case the timeouts
would go 1, 2, 4, 8, etc...