Re: [squid-users] Number of Objects Inside aufs Cache Directory

On 3/09/2013 10:29 a.m., Eliezer Croitoru wrote:
> Hey there,
>
> Since squid holds an internal DB there is no lookup that should be done
> on the file system level such as "ls |grep file_name" in order to find
> the file and to fetch all the details from the indoe.

FWIW: There is a translation step done in the OS to convert file path to
inode value (Squid does not know that bit). This usually involves a scan
of the directory listing in the FS itself (be it a list/tree walk, hash
lookup, or whatever). It doubtless has a lot of FS-specific optimization
which leads to varying results by different people tuning, but still
takes some few nano- or pico-seconds however it gets sliced.
  I believe this is what Duane was referring to in that quoted text.
However, notice also that he couches it as supposition and uses
"probably" on the advice conclusion. This is theoretical. I expect that
there were feedback reports (ie "Some people seem to think ...") but no
factual detailed analysis backing the idea. You may be able to find some
analysis on it if you can spare the time to dig into storage peoples
documentation and analysis - but I've never had that much time, s for
now ... "your mileage *will* vary": experimentation on your production
boxen is needed to know for certain.

But yes, overall you do not want to stress the FS directory limit if you
can avoid it with a small tweak in the config.

Amos
Received on Tue Sep 03 2013 - 12:11:17 MDT