Mailing List Archive

Hi there,

On Thu, 2 Sep 2021, Karakanovski, Anton via clamav-users wrote:

> ... we try to make three scans at a same time (some kind of
> performance test using jmeter) but unfortunately only the first scan
> is successful and the rests are with code 2 instead of 0.

Please tell us more. What exactly do you do to run three scans
simultaneously? Please give main specifications of the machine(s) on
which this is done - especially the amount of memory available.

> I found in clamAV documentation that clamscan is "one-time scanning"
> but couldn't understand much.
> ...
> Can you please explain what is the actual limitation for clamscan
> and what means "one-time scanning" - does it mean that only one scan
> engine could be initiated at a time or only one file could be scan?

If you mean this in the documentation:

https://docs.clamav.net/manual/Usage/Scanning.html?highlight=one-time%20scanning#one-time-scanning

then the term "one-time scanning" which you have quoted does *not*
mean that clamscan can only scan one thing at a time. It simply means
that there are many ways to use ClamAV, and doing a "one-time" (or
what others might call a "one-off" scan) is one of them.

ClamAV can indeed scan more than one thing at a time. Search for
'multiscan' in the documentation. You can even run more than one
clamd daemon on the same machine. I've run up to four. But if you
use the official signature databases, you will need enough memory so
that each clamd (and if you use clamscan, each one of those too) will
have about a gigabyte available for its use - and perhaps another one
gigabyte (each) during database reloads. If you staggered reloads so
that they don't all reload at once, you might be able to share that
extra gigabyte between the processes. Just a bit of juggling.

--

73,
Ged.

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On 02.09.21 15:45, Karakanovski, Anton via clamav-users wrote:
>I am writing regarding more information related to usage of clamscan.
>First I want to share the problem/observation that we have - currently we
> try to make three scans at a same time (some kind of performance test
> using jmeter) but unfortunately only the first scan is successful and the
> rests are with code 2 instead of 0.

how much of memory do you have? clamscan can take ~1.5GB

>I found in clamAV documentation that clamscan is "one-time scanning" but
> couldn't understand much. Also try find some information in the archive
> but actually with no result.
>Can you please explain what is the actual limitation for clamscan and what
> means "one-time scanning" - does it mean that only one scan engine could
> be initiated at a time or only one file could be scan?

it means that clamscan loads virus database, scans file/files and exits.
It can scan multiple files or directories, one after another and then it
exits.

for each clamscan run, it needs to load virus database again, which can be
most CPU expensive operation.

--
Matus UHLAR - fantomas, uhlar@fantomas.sk ; http://www.fantomas.sk/
Warning: I wish NOT to receive e-mail advertising to this address.
Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
"Where do you want to go to die?" [Microsoft]

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https://github.com/vrtadmin/clamav-faq

http://www.clamav.net/contact.html#ml