Measuring spare capacity

[Julian Field]

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I would advise you install MailScanner-MRTG or some other light-weight
monitoring package on the server to produce some graphs to provide
useful info on how the load is spread through the day.

Martin Hepworth wrote:

> Hi
>
> what hardware and what OS/MTA???
>
> what performance tuning have you done
>
> what does load average look like?
>
> might want to reduce batch set and max children to see how it gets
> on..theses params are very much trial and error...
>
> MailScanner wrote:
>
>> I am trying to get a handle on the amount of spare capacity in my MS
>> boxes.
>>
>> We are running two MS which handle about 250,000 messages by day (MRTG
>> count by recipient). The 'Max Unscanned Messages Per Scan' and Max
>> Unsafe Messages Per Scan' are both set at 50 and max children at 15.
>>
>> I isolated a day's worth of maillog entries out of a rotated file and
>> looked at some stats. Counting all instances of 'Found X messages
>> waiting' I found that 75% had just one message, 17% two, 5% three and
>> the more populous batches hardly registering at all. Doing the same for
>> 'Scanning X messages' I found a slightly wider spread but tapering off
>> quickly after 15.
>>
>> These are the distributions for the first 15 counts:
>>
>> New Batch: Scanning $a messages,
>> 1       36153
>> 2       8187
>> 3       2188
>> 4       767
>> 5       319
>> 6       139
>> 7       70
>> 8       45
>> 9       18
>> 10      11
>> 11      17
>> 12      6
>> 13      4
>> 14      3
>> 15      5
>>
>> Found $a messages waiting
>> 1       0
>> 2       7545
>> 3       7019
>> 4       5126
>> 5       3484
>> 6       2535
>> 7       1724
>> 8       1238
>> 9       915
>> 10      618
>> 11      489
>> 12      372
>> 13      260
>> 14      211
>> 15      161
>>
>> This surprised me. I was expecting the batch size to grow during busy
>> periods. It seems that the batch size is generally a single message,
>> even though more messages are waiting to be processed. Looking at log
>> snippets in the mailing list archives confirms that this is common.
>> Looking at the time distribution of (rather rare) larger batches I found
>> these spread randomly over the day.
>>
>> We regularly get a peak in the incoming messages queue of a few
>> thousands of messages. This makes me believe that there is not that much
>> slack in the capacity. During these peaks the number of messages per
>> batch does go up to the maximum.
>>
>> Is there a way to measure how many more messages per day a given system
>> can take?
>>
>> Thanks for any ideas.
>>
>> Bart...
>

--
Julian Field
www.MailScanner.info
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