[Samba] high cpu load with share_conflict on browsing and opening files

[Jeremy Allison]

On Tue, Oct 16, 2018 at 04:26:37PM +0200, Alberto Cavaliere via samba wrote:
> Hello,
> 
> I have a server  running samba version 4.7.1 on centos 7.5
> 
> 1) A series of operations by a windows 10 (up to date) pc client consisting
> of  searching (or browsing)/opening/modifying/closing a (each time
> different) file multiple times on a samba share containing many files (more
> than 11000) goes fast for a while.
> 2) Then the same operation (or just the searching or opening) of the same
> user on the same pc on the same dir gets very very slow (up to a minute) and
> the cpu of the pid samba process serving the user stays  over the 60% load.
> 3) Restarting the pc client doesn’t resolve the problem because it gets
> always served by the same (high cpu load) samba pid.
> 4) The same operations on a different pc (by the same user or not, doesn’t
> matter) are fast as long a they are served by a different samba process
> (otherwise is just as slow).
> 5) Restarting samba makes the problem go away for a short while, depending
> on how many operations described in 1) are made.
> 
> Please can sameone  give some pointers on why this is happens?
> 
> Thanks a lot (I'm in a very tight spot because of this)
> --------------------------------------
> Smb.conf:
> 
> client ipc signing = auto
> oplocks=no
> level2 oplocks=no

Why are you turning off oplocks. They are a big
performance enhancement. Ensure you're using SMB2
also.