[clamav-users] clamd cache (was Re: clamscan --disable-cache)

[Dave Sill]

"G.W. Haywood via clamav-users" <clamav-users at lists.clamav.net> wrote:
> 
> Perhaps try enabling libclamav debug logging.

I poked around a bit and didn't see an obvious way to do that, like a
configure option or a .h file. Couldn't really tell where it would be
logging.

> During your scans I suspect that ClamAV may be reaching some limit(s)
> which is causing caching to be disabled.  The limits are mostly
> tunable (in some cases perhaps care may be needed to avoid a DOS).

Played around with MemoryLimit=infinite in the systemd unut file and
didn't see that it helped. One thing that did help was the -m/--multiscan
option to clamdscan. Depending on the number of cores, I've seen scans
2-5x faster.

Interestingly, I just ran some more tests on my Fedora 32 desktop, and I
see caching working great:

# clamdscan --fdpass ~dave/Mail
Time: 932.016 sec (15 m 32 s)

# clamdscan -m --fdpass ~dave/Mail
Time: 90.140 sec (1 m 30 s)

# clamdscan -m --fdpass ~dave/Mail
Time: 12.845 sec (0 m 12 s)

# clamdscan --fdpass ~dave/Mail
Time: 9.975 sec (0 m 9 s)

# clamdscan -m --fdpass ~dave/Mail
Time: 3.102 sec (0 m 3 s)

# find ~dave/Mail -type f |wc -l
26675

So, time to test RHEL 8 and Ubuntu.

Thanks, Ged!

-Dave