[Samba] Slow response after moving to ver 4.10

[Jeremy Allison]

On Wed, Jun 30, 2021 at 07:45:42PM +0000, Jim Brand via samba wrote:
>New CentOS 7 file server, samba version 4.10.4-11 with 2,000 shares on multiple Gluster mounts.  Roughly 200-300 concurrent users.  We recently migrated this working
>setup from a CentOS 5 server (Samba 3) using  LDAP.  A few weeks later we started noticing sporadic slowdowns on our Windows 10 PC clients.
>Directory listings that normally take a few seconds can take many minutes if they finish at all.
>
>Nothing jumps out in the Samba logs.  A local linux find on the affected shares does not vary much, about a minute.  I've run smbclient 'recurse;ls' on the share(s) both locally and
>from another Linux host.  Local and remote search times (good and bad) agree closely:  A few minutes is normal but can take an hour or more when we're having problems.  Gluster or network is not suspect.  Sometimes cycling smb fixes it for a while but not today.
>
>This happens mostly during business hours but the server is always 95% idle.  Any ideas or what to look for in the logs would be appreciated.
>
>smb.conf:
>
>[global]
>kerberos method = system keytab
>log level = 3
>max log size = 5000
>log file = /var/log/samba/log.%h.%m
>template homedir = /home/%U@%D
>template shell = /bin/bash
>security = ads
>realm = MYGROUP.COM
>idmap config MYGROUP : range = 1034-2999999
>idmap config MYGROUP : backend = ad
>idmap config MYGROUP : schema_mode = rfc2307
>idmap config MYGROUP : unix_primary_group = yes
>idmap config MYGROUP : unix_nss_info = yes
>idmap config * : range = 10000-15000
>idmap config * : backend = tdb
>winbind use default domain = yes
>winbind refresh tickets = yes
>winbind offline logon = yes
>winbind enum groups = no
>winbind enum users = no
>workgroup = MYGROUP
>realm = MYGROUP.COM
>
>include = /usr/local/custom.conf
>
>Thanks,
>Jim Brand

Can you reproduce this from the Windows clients using
a command line listing, or only from Windows explorer ?

I think explorer gets more meta-data than a raw cmd.exe
"DIR" will do. That might give a hint on where to look.