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From Eldho <>
Subject Re: MySQL Virtual Host and Traffic Module
Date Fri, 17 Apr 2009 18:49:13 GMT

Hi Vaughan,

What is the status of this module. Actually I am searching for a module 
that write all the vhost  configuration to a database and read it from db



Dave Ingram wrote:
> Hi Vaughan,
>> Thanks for the response. I haven't thought of doing the SQL query the way
>> you suggested, however I agree that it will cause unnecessary load on
>> busy
>> servers and I would like to keep this as efficient as possible.
>> The second option sounds more reasonable. I have already used threading
>> to
>> make a function which ticks on a configurable interval so I suppose each
>> child process would dump data for each of its vhosts at this interval,
>> using
>> a query similar to what you have suggested.
> I think that's probably the most sensible approach. It does mean that 
> you won't have up-to-the-moment statistics, and I would guess that you'd 
> have to play about with different intervals as the number of hosts grows 
> in order for it to scale. You may also want to consider somehow 
> staggering the updates, so they don't all happen at once. It may also be 
> advisable to perform an UPDATE rather than an INSERT... ON DUPLICATE 
> UPDATE once your module knows that there is a value that can be updated 
> (i.e. after the query has run once in the simple case, or once this 
> day/hour/etc in the complex case).
>> I think I might go with the second option for the time being and see how
>> it
>> goes but I am still interested to know if there is a way to store per
>> vhost
>> data across children?
> I would be interested to know how things turn out, and I'd be interested 
> to see the final module. I've been thinking about writing a custom 
> bandwidth monitoring/limiting module myself, but if I don't need to 
> reinvent the wheel...
> I'm afraid I can't answer this question in a definite way, though. One 
> module that should store per-vhost data like this is mod_cband 
> <>, so that might be worth looking 
> into.
> As a side note, I'd be interested to know how you create/template the 
> virtual hosts. I myself have written a database-backed templating module 
> that could be used for virtual hosting 
> ( and I'm curious to 
> see other approaches.
> Thanks,
> Dave
>> Thanks,
>> Vaughan
>> -----Original Message-----
>> From: Dave Ingram [] 
>> Sent: Thursday, 19 March 2009 12:28 AM
>> To:
>> Subject: Re: MySQL Virtual Host and Traffic Module
>> Vaughan,
>>> What I have so far are 2 filters which gather the inbound traffic and
>>> outbound traffic for each transaction. These work ok and when logging
>>> transactions to file all of the in/out byte amounts appear to be
>>> correct.
>>> The first problem however, is that each child has its own set of memory
>> and
>>> therefore keeps its own totals per virtual host. This also means that
>>> multiple logging events occur for each transaction. I could just log
>>> this
>>> all to database but it would 1) be inefficient and 2) cause the size of
>> the
>>> database to grow quite quickly.
>> It sounds to me like you could go two ways with this. I don't know the
>> format of your database table, but it should be possible to update it
>> atomically using something like:
>> INSERT INTO bandwidth (vhost_id, bw_in, bw_out) VALUES (42, 1124,
>> 5023409) ON DUPLICATE KEY UPDATE bw_in = bw_in + 1124, bw_out = bw_out +
>> 5023409
>> but that could lead to a lot of load. Another way might be for each
>> child to collect statistics and only flush to the database periodically,
>> say every 30 seconds (perhaps configurable on a per-vhost basis, so that
>> load-heavy sites could have larger update intervals). It would still be
>> possible to use the query above though.
>> This query could probably even be updated to split statistics on a
>> date/time basis, if you require more granular reporting.
>> Or have I missed/misunderstood something?
>> Dave

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