samba - Sep 2014 - getent group empty response for multiple domain configuration when one domain controller is down

We have two domain controllers, one parent(DOMAIN.COM) and one child(
CHILD.DOMAIN.COM). When two domain controllers are up "getent group"
returns group names correctly. But when child domain controller is down
"getent group" returns empty. My samba version is "3.6.22".
I have added my
smb.conf I couldn't find any parameters affecting this problem. Am I
missing something in smb.conf? Or is there a workaround to solve this
problem?


smb.conf
-------------------------------
[global]
   netbios name = BUILD2
   realm = DOMAIN.COM
   workgroup = DOMAIN
   security = ads
   encrypt passwords = yes
   password server = 10.0.0.59
   log level = 1
   log file = /var/log/samba.log
   ldap ssl = no
   idmap uid = 10000-20000
   idmap gid = 10000-20000

   winbind separator = /
   winbind enum users = yes
   winbind enum groups = yes
   winbind use default domain = yes

   domain master = no
   local master = no
   preferred master = no

   template shell = /sbin/nologin

   getwd cache = yes
   winbind cache time = 3000
   ldap connection timeout = 10
   ldap timeout = 120
-------------------------------

This issue is like mine "
https://lists.samba.org/archive/samba/2010-June/156813.html".