[Samba] slow streaming but fast copy

[Tom Van den Eynde]

Hi List,

I have some very strange problems with samba on my shiny new server.

The first problem was that file transfers were very slow (copying a
file of 700Mb took 50 minutes over 100Mbit network). I checked other
protcols (ftp/http/scp) on the server and they were able to use the
100Mbit link for full. After a lot of debugging, I found that the
problem was related to oplocks. When disabling oplocks, the same file
was copied in just under 2 minutes.

However a second problem occured. Although copying files of the samba
file share works perfectly, playing mp3 files of the share does not.
When I open up any mp3 player and want to play a file, it stutters and
it is impossible to listen to. With Winamp, I mangaged to get some
quality by setting the buffer to 100Mb but I don't want to do this at
every pc and in every mp3 client.
I tried different settings (tcp_nodelay, SNDBUF, SRVBUF, TCP_TOS) but
no effect there.
I also ran a tcpdump when copying a file (good) and when streaming a
file (bad) but there are no noticable differences there.

On the samba server, there is also a VMware server running so I tried
setting up a Win VM in there (on the same physical server) and when I
stream files from the Windows VM, I have no problems whatsoever

This leads me to believe that there is a problem with either samba or
the linux kernel.

The server specs are the following:
Hardware: Core 2 Duo 6600, 2 GB DDR RAM, 500 GB SATA, Asus Mobo with
Realtek 10/100/1000 NIC
OS: Debian Stable 3.1, Linux Version 2.6.19.1 SMP
SAMBA: 3.0.23d (from apt repository at samba.org)
Sanitized smb.conf:
[global]
   panic action = /usr/share/samba/panic-action %d
    workgroup = TESTGROUP
    netbios name = server
    server string = VDE Server
    hosts allow = 1.2.3.4
    printcap name = cups
    load printers = yes
    printing = cups
    log file = /var/log/samba/log.%m
    max log size = 500
    log level = 1
    security = user
    encrypt passwords = true
    passdb backend = tdbsam
    smb passwd file = /etc/samba/smbpasswd
    unix password sync = Yes
    passwd program = /usr/bin/passwd %u
    passwd chat = *New*UNIX*password* %n\n *ReType*new*UNIX*password*
%n\n *passwd:*all*authentication*tokens*updated*successfully*
    socket options = TCP_NODELAY
    oplocks = no
    level2 oplocks = no

    interfaces = 1.2.3.4/24

    local master = yes
    os level = 65
    domain master = yes
    preferred master = yes
    time server = yes

    domain logons = no
    wins support = yes
    dns proxy = yes
    preserve case = yes
    short preserve case = yes
    case sensitive = no

[mp3]
    path = /home/mp3
    comment= MP3 disk
    public = yes
    guest ok = yes
    writable = yes
    printable = no
    force user = nobody
    force group = nogroup

Does anyone has a clue what might be wrong?
Oh yeah, the same smb.conf worked perfectly on the old server (with
oplocks enabled that is)

Many thanks,

Kind regards,

Tom