Our server is performing decently, but when backups or other scan processes run it will tank the entire server. Something like clamd will run and scan many files. While we expect slow performance, it's killing our cache and the end result is we don't get a system that can do anything.
Is there a way to disable disc/disk caching for a single command? The idea would be to run it like this:
# ./nocache clamd
Then while running clamd it would not thrash the primed cache while reading all the files on the system.
Best Answer
It has to be implemented in the program itself. If
clamddoesn't already do it, you can modifyclamdto avoid an unnecessarily large cache footprint by adding calls to functions likeposix_fadvise(... POSIX_FADV_NOREUSE)ormadvise(... MADV_DONTNEED)(if it memory maps the files). It will still push filesystem metadata out of the cache though. There's not much you can do about that.