Fwd: Help Needed: Samba share slow to query not existing files

Jeremy Allison jra at samba.org
Wed Jan 20 18:20:55 UTC 2021

On Wed, Jan 20, 2021 at 02:37:45PM -0300, Jônatas Hudler via samba-technical wrote:
>Hello everyone,
>*(First mail in this mailing list, so take it easy if I'm infringing any
>good manners here)*
>In a samba share we have a directory with lots of files - binaries and
>resources to run our ERP application (around 20K entries).
>The application is taking too long to load. The found reason is that the
>application tries to load several files in a trial/error fashion, looking
>for extensions in a particular order (e.g: file.dll, file.lbr, file.gnt,
>file.int). Many of these files are not required and doesn't even exist.
>Every "not found" hit take ~0.2 seconds. And there are lots of these events.
>The thing is that apparently samba is not caching this result. My guess is
>that every new not existing file open request causes a full directory's
>entries lookup.
>If I run this code (in a Windows Command Prompt) in this samba share, it
>takes considerable time, whereas in a native Windows share it is
>  for /L %i in (1,1,50) do @dir \\server\share\not_existing.txt >nul
>Anything that can be done?

You are running into the classic "large directory performance"
issue, caused by Samba having to run on top of a POSIX case-sensitive

Here's the brute force fix:


NOTE!!! from the text:

"All files on the share must be converted to lowercase when using the example.
Files using uppercase or both uppercase and lowercase are no longer listed on the share."

Or switch to a filesystem the supports case insensitive
lookups (I think xfs or zfs can do this).

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