openstack team mailing list archive

[Klaus Schürmann <klaus.schuermann@xxxxxxxxxxxxx>]

Hi Rick,

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.

Thanks
Klaus

-----Ursprüngliche Nachricht-----
Von: Rick Jones [mailto:rick.jones2@xxxxxx] 
Gesendet: Freitag, 31. Mai 2013 19:17
An: Klaus Schürmann
Cc: openstack@xxxxxxxxxxxxxxxxxxx
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...

rick