[Samba] Slow response after moving to ver 4.10

[Jim Brand]

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


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