[Samba] What controls the Read AndX Request byte size?

Steven Cardinal steven.cardinal at gmail.com
Fri Sep 29 12:45:08 GMT 2006

In trying to track down some performance issues, I'm finding with Ethereal
that, when I launch an application from my Windows server, the SMB Read AndX
Request packets have Min Count, Max Count Low, and Remaining all at 512
bytes. When launching the same application on the same client from a Win2000
share, these requests are coming in much larger sizes (4096 and 32768 were
both observed). This is making a huge difference in the launch speed of the
application (an in-house VB app).

My question is, what smb.conf or kernel parameters could be influencing the
512 byte read request? I tried setting various socket options in
smb.confand haven't seen a change. I am running Suse
10.0 with their 3.0.20b samba packages (except we recompiled to include

My global settings are:

        unix charset = LOCALE
        workgroup = MYDOMAIN
        realm = MYDOMAIN.INT
        server string = Production File Server 03
        security = ADS
        allow trusted domains = No
        enable privileges = Yes
        username map = /etc/samba/smbusers
        log level = 10
        log file = /var/log/samba/%m
        max log size = 50
        socket options = IPTOS_LOWDELAY TCP_NODELAY SO_RCVBUF=8192
        printcap name = cups
        wins server =
        ldap ssl = no
        idmap backend = idmap_rid:MYDOMAIN=10000-50000
        idmap uid = 10000-50000
        idmap gid = 10000-50000
        template shell = /bin/bash
        winbind separator = +
        cups options = raw


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