[Samba] Slow winbind lookups

[Alex Matthews]

Hi all,

I have a Samba 4.0.0 domain running on a Gentoo box with a 3.7.0 kernel.
I have added 'winbind' to the passwd and group lines in /etc/nsswitch.conf

wbinfo -t returns immediately saying trust checking succeeded.
wbinfo -g returns immediately with a list of groups
wbinfo -u takes a long time to return a list of users

# time wbinfo -u | wc -l
336

real    0m4.211s
user    0m0.000s
sys     0m0.000s

4s might not seem like a great deal but this delay seems to occur 
whenever anything looks up data from winbind.

getent passwd also has a similar delay. It returns local users 
immediately but winbind users are delayed. Whilst gathering data for 
this post I have noticed that the results also seem to be sporadic. The 
following 3 commands were run in quick succession:

# date && time getent passwd | wc -l
Thu Jan 10 09:41:22 GMT 2013
376

real    0m5.677s
user    0m0.010s
sys     0m0.000s

# date && time getent passwd | wc -l
Thu Jan 10 09:41:29 GMT 2013
220

real    0m2.633s
user    0m0.000s
sys     0m0.000s

# date && time getent passwd | wc -l
Thu Jan 10 09:41:32 GMT 2013
235

real    0m4.014s
user    0m0.000s
sys     0m0.010s



Another example would be samba-tool sysvolreset:

# time samba-tool ntacl sysvolreset

real    5m26.076s
user    3m7.500s
sys     0m13.480s

and if I disable winbind in nsswitch.conf

# time samba-tool ntacl sysvolreset

real    1m13.851s
user    0m46.500s
sys     0m3.140s

(1m still seems to be a long time for this process to complete but I'll 
save that for my other post)

Is this correct speed? Is there anything I can do to improve performance?

Thanks,

Alex