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From Rainer Jung <rainer.j...@kippdata.de>
Subject Re: mod_jk 1.2.17+ Recover time
Date Wed, 26 Jul 2006 16:36:01 GMT
Hi David,

David Rees schrieb:
> On 7/25/06, David Rees <drees76@gmail.com> wrote:
>> On 7/24/06, David Rees <drees76@gmail.com> wrote:
>> I spoke too soon. I've been testing 1.2.18 further, and recover time
>> while appearing to change, I can not get mod_jk to actually recover
>> any faster than 60 seconds, even when recover time is set to 1.
> 
> OK, It seems that the docs could use some clarification (can't be good
> if the devs seem to be a bit confused as well as to what they do), but
> you also need to set worker.maintain to a low value as well. mod_jk
> acts like it uses the minimum of either worker.maintain or the
> lb_worker's recover_time to determine the minimum amount of time a
> worker should be down.

At least concerning thi spoint we devs had no confusion. The docs under
dist have been updated when 1.2.18 has been put on dev:

http://tomcat.apache.org/dev/docs/tomcat-connectors-1.2.18/config/workers.html

says for recover_time:

The recover time is the time in seconds the load balancer will not try
to use a worker, after it went into error state. Only after this time
has passed, a worker in error state will be marked as in recovering, so
that it will be tried for new requests.

This interval is not checked every time a request is being processed.
Instead it is being checked during global maintenance. The time between
two runs of global maintenance is controlled by worker.maintain.

Do not set recover_time to a very short time unless you understand the
implications. Every recovery attempt for a worker in error is done by a
real request!

And worker.maintain is explained as:

Worker connection pool maintain interval in seconds. If set to the
positive value JK will scan all connections for all workers specified in
worker.list directive and check if connections needs to be recycled.

Furthermore any load balancer does a global maintenance every
worker.maintain seconds. During global maintenance load counters are
decayed and workers in error are checked for recover_time.

This feature has been added in jk 1.2.13.

> 
> By setting worker.maintain to 10 and lb_worker's recover_time to 10 I
> can get a reasonable recovery time for a worker.
> 
> -Dave

Expect 1.2.18 and the new doc to become official very soon :)

Rainer

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