Server Loads/hardware standards - recommendations

[Julian Field]

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Scott Silva wrote:
> Julian Field spake the following on 10/17/2006 12:29 PM:
>   
>> Scott Silva wrote:
>>     
>>>> Michael Kain spake the following on 10/17/2006 9:52 AM:
>>>>   
>>>>         
>>>>> Recently, I've gone from handling 40k messages /day to nearly 30k/hour. 
>>>>> The change has surfaced in the last month or so.
>>>>>
>>>>> My current setup:
>>>>> Dual P3 1.13
>>>>> 1GB Ram
>>>>> FC5
>>>>>
>>>>> Mail gateway running MS/clam/SA forwards scanned mail to internal mail
>>>>> server (when there's a problem, users hit send/receive and that doesn't
>>>>> cause an error..thus avoiding immediate call) I've used Julian's clam/sa
>>>>> install script (which is awesome), and read posts relating to new
>>>>> releases before upgrading/such.
>>>>>
>>>>> With spamassassin enabled, the batch list grows and grows, was up to 95k
>>>>> at one point.. disabling SA in MS cleared that out fairly quickly.  I've
>>>>> wiped the SA/bayes temp files thinking bayes was backing up, however, it
>>>>> seems that is not helping.
>>>>>
>>>>> What I would like an opinion on is this... Am I trying to do too much
>>>>> with the hardware that I currently have?  Or do I put together a bigger
>>>>> beefier machine?
>>>>>
>>>>> -Mike
>>>>>     
>>>>>           
>> You can make a huge difference to the amount of spam you have to process 
>> with 2 tools:
>>
>> 1) milter-gris
>> 2) milter-null
>>
>> Number 1 implements grey-listing. There are a lot of discussions about 
>> greylisting on the web, and a lot of people are very wary of it 
>> initially. I was too. Then I ran a test with a handful of the fussiest 
>> email users I have (I've got about 2000 users in total). I told them I 
>> was implementing something new, but refused to tell them what, so they 
>> would not have any pre-conceptions about it. They *all* loved it, and 
>> none of them reported any problems at all. So I implemented it across 
>> all of my users, who are very fussy Computer Science and Electronics 
>> academics, as well as the students. That was about 6 months ago, since 
>> when I have had *1* complaint, which I dealt with by adding them to the 
>> whitelist for it.
>>
>> So my conclusion with greylisting is test it with some very fussy users, 
>> then roll it out to everyone.
>>
>> Number 2 implements back-scatter detection. Basically, what this does is 
>> get rid of all the "This message could not be delivered..." notices that 
>> weren't generated in response to your own users' mail. It doesn't throw 
>> away all of them, so that if your users mistype an address, they still 
>> get the error message from it. But all the delivery failure messages 
>> generated by forged spam get killed.
>>
>> Between these 2, you will remove 80-90% of all the mail coming into your 
>> site, without losing any genuine real mail at all. This will make your 
>> hardware go a hell of a lot further, and you will find you don't need to 
>> spend any money on new hardware at all.
>>
>> My MX servers used to just about cope. Then I implemented these 2 
>> techniques and they now just tick along quite happily, getting very bored.
>>
>> Both of the above techniques can be done very easily in sendmail and 
>> Postfix using the milters which are available from www.snertsoft.com. I 
>> thoroughly recommend them to everyone.
>>
>> Jules
>>
>>     
> So the addition of the two milters doesn't add that much load?
>   
No, they don't. And they save way more load than they cause!

Jules

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