[Samba] Samba Version 4.1.9-Zentyal (Zentyal4.0) is using a lot of RAM memory to crash

[Denis Morejon]

I have been using two Zentyal 4.0 domain controllers for a long time.
3Gb of RAM each one and working okay. I have not updated them from
Internet and my users are the same. Suddently, the first DC began to 
comsume memory to the top.
I detected that samba processes are the responseble of this behavior.
More processes with more memory come on. They get more and more memory
in such a way that the server crash in one day. If I add more memory 
size (5Gb) to this
virtual machine it crash anyway when it reach that new size.

I have two possible solution:

1- To find a fix
     A lot of solutions are related with upgrade the samba and the 
kernel version but no thing about
     change a configuration, or something like that.

2- To replace the domain controllers with new ones (Version 
4.3.11-Ubuntu, Ubuntu 16.04). Because It should be difficult
      to upgrade the current ones (They are too old versions).
      Following this way, I demoted the 2nd Zentyal and tried to add the 
Ubuntu 16.04 as a second domain controller using
      the primary Zentyal as controller, but It got this error in the 
replication process and can not join to the domain:
====================================================================
      Replicating critical objects from the base DN of the domain
     Partition[DC=dtcf,DC=etecsa,DC=cu] objects[100/100] 
linked_values[36/0]
     Partition[DC=dtcf,DC=etecsa,DC=cu] objects[502/43088] 
linked_values[0/0]
     Partition[DC=dtcf,DC=etecsa,DC=cu] objects[904/43088] 
linked_values[0/0]
     No objectClass found in replPropertyMetaData for CN=PC006870-HP 
Lase0015007130\0ACNF:8027e2d4-47e9-4f26- 
abaa-3630fde07618,CN=PC006870,OU=ECONOMIA,OU=CFG,DC=dtcf,DC=etecsa,DC=cu!
====================================================================

      How to fix this specific replication problem ? Or how to keep the 
Zentyal 4.0 from getting more memory resources?

Thanks in advance!