[Samba] Samba4 shares slow

[Julien TEHERY]

Hi there

I set up a POC domain with multiple DCs, multiple remote sites and samba 
shares. This POC is a simulation of a whole samba3 domain migration.
Users, and groups have been imported from the older domain to the new one.

Here's the setup:
("Remote sites" are actually different subnets on the same location for 
the POC)

*Main Site*:
DC1 (RHEL7 - samba 4.6.4)
DC2 (RHEL7 - samba 4.6.4)
DC3 (RHEL7 - samba 4.6.4)
SMB1 (Ubuntu 14 - samba 4.3.11+dfsg-0ubuntu0.14.04.14)


*Remote_Site_1*
DC4 (RHEL7 - samba 4.6.4)
SMB2 (Ubuntu 14 - samba 4.3.11+dfsg-0ubuntu0.14.04.17)

*Remote_Site_2*
DC5  (RHEL7 - samba 4.6.4)
SMB3 (Ubuntu 14 - samba 4.3.11+dfsg-0ubuntu0.14.04.17)

*Remote_Site_3 *
DC6  (RHEL7 - samba 4.6.4)

The samba servers/shares are inherited from the former samba3 domain. I 
updated them and joined them to the new samba4 domain.


Users in the samba4 domain can access those migrated shares  (with their 
fomer uid/gid as I imported their former unix attributes from the old 
samba3 domain).

BUT

Here is the thing:

If I try to access to an SMB1 share: absolutely no problem (fast access, 
no acls problems)
If I try to access to an SMB2 or SMB3 share from a win7 client: access 
is ok but extremely slow (acls are fine too)
Same access to SMB2 or SMB3 with smbclient is fine.

So..what can cause the win7 client to be very slow with only SMB2 and SMB3 ?