What are the limitations of ip_hash ?

Mark Swanson mark at ScheduleWorld.com
Wed Dec 31 20:33:15 MSK 2008

Dave Cheney wrote:
> Indeed - what does your error log say ? I notice you have max fails=0

Error log: er... hold the phone...
I've just finished some analysis of the session conversations and found:
1. Funambol client connects to SWorld to start a sync.
2. Funambol client takes 80 minutes to figure out what to send.
3. Funambol client sends, and fails because the session timed out and
has been deleted.

When a session is terminated it looks like nginx is routing a request to
the wrong machine because the session isn't there, but it's not nginx's

I have no evidence that nginx ip_hash is at fault.
I'm sorry for the noise. I'm thankful for the responses.

> which means (AFAIK) that a temporarily failed backend will be re added
> to the queue immediately.

I did this because the docs don't state what to look for in the
error.log file if a server is marked as inoperative. I was worried that
a server was being marked as inoperative and the requests are being sent
to the wrong machine. I should be able to force this condition and
derive the text from the logs. If I get around to doing this I'll post
to the list.


> Cheers
> Dave
> On 31/12/2008, at 8:52 PM, Grzegorz Nosek wrote:
>> If I understand the source correctly, this happens when one of your
>> backends is down (as determined by Nginx). The IP address is then
>> rehashed and the connection retried until it succeeds or you run out of
>> backends.

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