[SAC] Mailman Postfix tuning - Urgent

Alex Mandel tech_dev at wildintellect.com
Fri Apr 18 19:21:55 PDT 2014


More progress, based on some advice, I looked at apache.
Turns out Apache is the cause of much of the i/o along with bouncing
emails. I added Buffered logs, but that didn't change much.

I've added a robots.txt with crawl delay since google and bing are all
over the logs. But there's also strange subscription patterns. For now
apache is off on Mail. I'll probably leave it off until the disk rebuild
finishes (eta end of weekend). So no new subscriptions till then. Any
volunteers to look more into this?

Looks like mail queue is now catching up to real time...

FYI started modifying grub to include elevator=noop to change the
scheduler (makes huge difference on QGIS and Projects) and picking
swappiness between 10-30 on various machines since we have no shortage
of ram.

Thanks,
Alex

PS: All the tips I'm putting in emails are coming from various sources
other than me, they are appreciated, so keep them coming.


On 04/18/2014 06:36 PM, Alex Mandel wrote:
> http://wiki.centos.org/HowTos/postfix_restrictions
> 
> Helo and Sender restrictions might help, by validating that senders have
> valid domains to start and follow standard practices.
> 
> We do have recipient restrictions enabled already.
> 
> FYI, I just tried uping the queue_run_delay to 600 from default 300. To
> try resending less often.
> 
> Thanks,
> Alex
> 
> On 04/18/2014 06:03 PM, Alex Mandel wrote:
>> Disk rebuild on osgeo4 is taking longer than expected. Not sure why, but
>> even with all the VMs off it was going at 2%/hour.
>>
>> After a couple of hours I turned on Mail so that we wouldn't impact the
>> mailing lists for too long. The problem here is that Mail is the biggest
>> i/o user on osgeo4.
>>
>> Poking around and reading up, I think there are some things that can be
>> done to make Mail behave better but would really prefer someone who
>> knows postfix step in and help out here.
>>
>> Ideas and observations:
>> Ram-disk for the queues? (Yes we can allocate more ram to the instance)
>>
>> We seem to have a high deferred queue, do we need to clean out bad
>> addresses? Perhaps increase the delay time, or spin off the deferred
>> queue to another "graveyard" server?
>>
>> Is apache being hammered by bots scanning the archives?
>>
>> Are there bot like things trying to subscribe, I see some odd @wp.pl
>> addresses in the apache logs, trying to hit many list in a few seconds
>> and then rotating the username.
>>
>> Are we using a local DNS cache?
>>
>> http://www.postfix.org/QSHAPE_README.html#deferred_queue
>> http://www.postfix.org/postconf.5.html#queue_run_delay
>>
>> Who's up for the challenge?
>>
>> Thanks,
>> Alex
>>
>> PS: I'll turn QGIS and Projects back on in a few hours. Hopefully this
>> can be tuned before that. Adhoc will likely stay off for the weekend.
>> _______________________________________________
>> Sac mailing list
>> Sac at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/sac
>>
> 
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> 



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