[Samba] gencache.tdb size and cache flush

[Francesco Malvezzi]

> Hai, 
> 
> 
> It might be handing to tell your OS and samba version. 
> A copy of smb.conf is also very handy.. 


oops, sorry.

samba-4.8.5 compiled from source on Debian GNU/Linux 9 (stretch).

smb.conf is:

[global]
	netbios name = ADDC
	realm = EXAMPLE.ORG
	workgroup = EXAMPLEAD
	dns forwarder = [redacted]
	server role = active directory domain controller
	log level = 1
        log file = /var/log/samba/log.%m
#	ldap debug level = 3
        interfaces = eth0, lo
        bind interfaces only = Yes
        tls enabled  = yes
        tls keyfile  = /opt/samba/private/tls/addc.key
        tls certfile = /etc/ssl/certs/addc.pem
        tls cafile   = /etc/ssl/certs/DigiCertCA.crt
	tls verify peer = ca_only
        ldap server require strong auth = allow_sasl_over_tls

	printcap name = /dev/null
   	load printers = no
   	printing = bsd

	idmap_ldb:use rfc2307 = yes
	template shell = /bin/mosh
	template homedir = /homel/%U
	kerberos method = secrets and keytab

[netlogon]
	path = /opt/samba/var/locks/sysvol/unimore.it/scripts
        root preexec = /opt/netlogon/netlogon.sh %U %M %a %I
	read only = Yes

[sysvol]
	path = /opt/samba/var/locks/sysvol
	read only = No


franz

> 
> Greetz, 
> 
> Louis
>  
> 
> 
>> 
>> Hi all,
>> 
>> I have a midsize AD domain with some 50k users but only 100 
>> workstations
>> joined.
>> 
>> Sometimes I find server CPU throttling at 100%. In order to 
>> let it drop
>> and have smooth performance I delete cache:
>> 
>> systemctl stop samba
>> net cache flush
>> systemctl start samba
>> 
>> First of all, is it needed a samba stop to flush the cache?
>> 
>> Even if cache flush does the job to restore performance, I am clueless
>> about the root cause of the problem. Before flushing cache the
>> gencache.tdb had 15k entries. Is it large? Do you think is it 
>> worth time
>> to investigate why it grows so much or is it just normal?
>> 
>> thank you,
>> 
>> franz