Upgrade to clamav 0.90.2 makes scanning extremely slow

Richard Lynch rich at mail.wvnet.edu
Fri Apr 27 16:12:50 IST 2007

Glenn Steen wrote:
> On 27/04/07, Richard Lynch <rich at mail.wvnet.edu> wrote:
>> Out of curiosity I decided to do a little testing of the performance of
>> the three ClamAV methods:  clamscan, clamdscan, and clamavmodule.  This
>> is not meant to be a full blown scientific test, merely a quick "rough
>> idea" measurement.
>> I have a directory  with over 300 virus infected files in it.  Running
>> the three methods shows...
>>    clamscan:           11.68 seconds
>>    clamdscan:           6.56 seconds
>>    clamavmodule:    4.50 seconds
>> Results for clamscan and clamdscan we obtained using the "time"
>> command.  Results for clamavmodule were obtained using the perl
>> Time::HiRes module.  I had to use that to avoid adding in the time for
>> the initial database load.
>> This is pretty much what I expected.  Clamavmodle is the quickest since
>> it doesn't have to load the database on every scan and it calls the
>> ClamAV libraries directly.   Clamdscan is next since it doesn't have to
>> load the DB every time but it does have the overhead of the
>> communications with the clamd process.  And clamscan is slowest (by a
> Don't forget the additional fork/exec bit either... Every cycle 
> counts:-).
>> significant margin) since it has to load the database on every batch.
>> So, performance wise, clamavmodule is the best.  However, it does have
>> the problem with being kept up to date with ClamAV changes.  Clamdscan
>> is a little slower but avoids the problem with development changes in
>> ClamAV.
> Yes, byt basically you are showing that Jules is right that there is
> no real big performance reason to implement clamdscan in MS... Then
> again, if enough people want it, he'll likely add it just to keep 'em
> quiet:-):-). ... Once he's well enough, of course.
> Cheers
Yes, Jules is correct from a performance perspective.  The issue then 
becomes clamavmodule being kept up to date.  The question is... "Is the 
loss in performance worth the benefit of not being dependent on a third 
party package???".  I can't answer that.  It depends! 
 From my perspective, clamscan is only worthwhile for low volume 
setups.  For high volume situations only clamdscan or clamavmodule can 
keep up.  My 2c.



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