[Samba] Strange lock problem + sporadic massive slowdown

[Michael Rignaz]

Hi,
thanks for reading, would be great if you could help me out with two 
strange reoccuring problems.

Problem 1:

Currently we are running an IBM 206m with Debian Etch and Samba 3.0.24.
We have about 25 Clients which are running Windows XP SP2 or 2000 SP4.
3 of those Clients (XP) open and close ~15 excel sheets (size between 
100kb and 1MB) approximately every 5 Minutes or so.
5-6 times a day it happens to them, that " 'everything' hangs" -as they 
tell me- for about 20seconds. They are using Windows Explorer for 
opening different smb shares, browsing and selecting excel files. When 
this happens, explorer and/or excel freeze for this amount of time. It 
doesn't seem as the cause being some  kind of networking problem. They 
are connected with gigabit ethernet (no rx/tx errors) and when this 
happens, while the problem persists, the network throughput from the 
affected clients to the server is excellent.
At those times the machine is ~98%idle. Could more Ram on the server 
help? We have 1 GB Ram and when all users are connected and acting, only 
about 14MB of free physical memory is left.Though that's really little, 
I didn't buy more memory yet, 'cause paged memory size is always near zero.
Could more ram and raising the values of SO_RCVBUF and SO_SNDBUF help? 
What would you suggest? Thanks!
Our options in the smb.conf are as follows:

socket options = TCP_NODELAY IPTOS_LOWDELAY SO_KEEPALIVE SO_RCVBUF=10240 
SO_SNDBUF=10240
domain logons = yes
preferred master = auto
utmp = Yes
map acl inherit = No
hide files = /.*/desktop.ini/
oplocks = False
level2 oplocks = False
log level=1
wins support = yes
reset on zero vc = yes

Problem 2:
Once in a week or two we experience the exact behavior as mentioned here 
: http://lists.samba.org/archive/samba/2006-August/123652.html, which 
was fixed in 23a already?
Files (in our case word docs) suddenly (often after a crash) are locked 
by the user who is actually trying to re-open the file (statically 
assigned ip address via bootp).
When I kill the user's process the lock is still active and stays while 
I can mv around the file as I want to. Only restarting the whole samba 
daemon fixes that.
This happend with several version 23 and now with 24 too. Anyone has a 
clue? :)


Thanks,

Greetz,
Michael