[Samba] Slow perfomance comparing Win NT 4.0 server

[Georgy Goshin]

Hello!

I've replaced the old Windows NT 4.0 server with new modern

(Core 2 DUO 2.4Ghz with 1GB RAM, SATA drives in linux software RAID 1 under 
CentOS 5, Samba 3.3.0-38)

But client started to complain that the speed was slowed down. I made some 
tests with old and new servers and see that working with files is really 
slow. Office and pdf documents opening sometimes up to minute comparing 1-2 
second from old server.

Please point me to the right way to catch the problem

hdparm shows good numbers:

/dev/md0:
 Timing buffered disk reads:  182 MB in  3.01 seconds =  60.48 MB/sec
/dev/md0:
 Timing cached reads:   4528 MB in  2.00 seconds = 2265.41 MB/sec




smb.conf:
#======================= Global Settings 
=====================================

[global]

        workgroup = CORP
        server string = MASTER Fileserver

        netbios name = master

;       interfaces = lo eth0 192.168.12.2/24 192.168.13.2/24
;       hosts allow = 127. 192.168.12. 192.168.13.

# --------------------------- Logging Options -----------------------------
        # logs split per machine
        log file = /var/log/samba/%m.log
        # max 50KB per log file, then rotate
        max log size = 250


        socket options = TCP_NODELAY SO_RCVBUF=8192 SO_SNDBUF=8192


# ----------------------- Domain Controller Options ------------------------
#
        security = user
        passdb backend = tdbsam

        domain master = yes
        domain logons = yes

        # the login script name depends on the machine name
;       logon script = %m.bat
        # the login script name depends on the unix user used
        logon script = %u.bat
;       logon path = \\%L\Profiles\%u
        # disables profiles support by specifing an empty path
        logon path =

        add user script = /usr/sbin/useradd "%u" -n -g users
        add group script = /usr/sbin/groupadd "%g"
        add machine script = /usr/sbin/useradd -n -c "Workstation 
(%u)" -M -d /nohome -s /bin/false "%u"
        delete user script = /usr/sbin/userdel "%u"
        delete user from group script = /usr/sbin/userdel "%u" "%g"
        delete group script = /usr/sbin/groupdel "%g"


# ----------------------- Browser Control 
Options ----------------------------
        local master = yes
        os level = 65
        preferred master = yes

#----------------------------- Name 
Resolution -------------------------------
        wins support = yes
#;      wins server = 192.168.0.10
#;      wins proxy = yes

#;      dns proxy = yes

# --------------------------- Printing Options -----------------------------
        load printers = yes
        cups options = raw

;       printcap name = /etc/printcap
        #obtain list of printers automatically on SystemV
;       printcap name = lpstat
;       printing = cups

# --------------------------- Filesystem Options ---------------------------
#
;       map archive = no
;       map hidden = no
;       map read only = no
;       map system = no
;       store dos attributes = yes

#============================ Share Definitions 
==============================

[homes]
        comment = Home Directories
        browseable = no
        writable = yes
        valid users = %S
        valid users = MYDOMAIN\%S


# Un-comment the following and create the netlogon directory for Domain 
Logons
[netlogon]
        comment = Network Logon Service
        path = /var/lib/samba/netlogon
        guest ok = yes
        writable = no
        share modes = no


# Un-comment the following to provide a specific roving profile share
# the default is to use the user's home directory
;       [Profiles]
;       path = /var/lib/samba/profiles
;       browseable = no
;       guest ok = yes



[Documents]
        path=/home/shares/Documents
        comment="Documents"
        writeable=yes
        browseable=yes
        create mode=0660
        directory mode=0770


[Invoices]
        path=/home/shares/Invoices
        comment="Invoices"
        writeable=yes
        browseable=yes
        create mode=0660
        directory mode=0770
        valid users = igor,larisa,sergei1

[Shared]
        path=/home/shares/Shared
        comment="Shared Files"
        writeable=yes
        browseable=yes
        create mode=0660
        directory mode=0770

[Source]
        path=/home/shares/Source
        comment="Software source"
        writeable=yes
        browseable=yes
        create mode=0660
        directory mode=0770