Performance issue on SMB share with Windows 10

Question

Hello,

I have some Windows 10 workstations with a SMB3 mounted share (on a Windows server) containing a directory structure with ~15k files.

When doing a recursive listing, the command (dir /s /b /a A: > list.txt) run in ~20s.

When doing a same test from a linux workstation with a mount point to the same share, the command (find /mnt/tmp/ > list.txt) run in ~5s.

Do someone have an explanation on that and how can I solve this issue ? This is very problematic to our Windows users to have such response delay.

Thx

Answer 1

Hello Jérôme,

The difference is probably attributable to the "programs" that perform the recursive listing and is not directly related to the operating systems (Windows vs. Linux).

Network and/or event tracing can be used to gain insights into what the programs are doing and where the time goes.

I don't have a Linux system to check the "find" command, but analysing the "dir /s /b /a" command provides some hints as to why it is slower. It appears to traverse each folder/directory twice: once to obtain the names of the entries in the folder/directory and once to identify folders/directories for recursion. Furthermore, for each directory discovered, two queries for properties are made (FileStandardInformation, FileBasicInformation) even though the data is not needed when the "/b" qualifier is present.

The Windows "dir" command is not necessarily badly coded - it appears that emphasis was given to flexibility and reusability. This is normally not a problem, but mapping this style to network protocol operations on large trees reveals a performance problem.

It would be possible to write a program that is as quick as Linux "find" and it might be possible to find some public domain utility that is coded that way; however, it would not be easy to convince your users to use it.

Gary