Windows<->VMS Samba performance issue
BG - Ben Armstrong
BArmstrong at dymaxion.ca
Fri Sep 17 19:49:04 GMT 2004
OK, now for the server end of things:
A weekend upgrade is scheduled, so here are current and after-upgrade
versions:
On Fri, 2004-09-17 at 14:04 -0500, John E. Malmberg wrote:
> VMS version?
OpenVMS 7.3-1 (upgrade will bring this up to 7.3-1 on Monday).
> TCPIP platform and version?
TCPIP V5.3 ECO 4 (upgrade will bring this up to V5.4 ECO 2 on Monday)
> Samba version?
2.2.8-20040908 (no change on Monday)
> There is one key difference in how some Microsoft Windows clients treat
> large files and how SAMBA does. SAMBA sends the file sequentially from
> start to finish. For some unknown reason, Microsoft Windows sends the
> first part of the file, skips a bit and sends the middle, and then backfills.
Our benchmark routine would prevent that sort of copying, wouldn't it?
It simply writes a stream of blocks sequentially.
> And it just may be a case where SAMBA to SAMBA transfers are more efficient
> than WINDOWS to SAMBA transfers, since you would expect that if it were
> really a server issue, that the server would perform badly for both clients.
A factor of 10X more efficient? I'm as inclined as the next Linux-
hugging geek to glibly say "well, Windows sucks, what do you expect?"
but that's a pretty huge discrepancy! That's what leads me to believe
it is simply a matter of things not being tuned optimally for Windows to
Samba communication, and yes, probably at the client end, but I don't
believe we can rule out the server out of hand.
> If you use a LINUX SAMBA server instead of a VMS SAMBA server, do you see
> the same difference in performance?
When I use a Linux Samba server, the numbers for the Windows client are
as follows:
C: (Local) ~0 sec
H: (WinXP) ~2 sec
G: (Linux Samba) ~15 sec
S: (OpenVMS Samba) ~76 sec
And considering that the Linux Samba server is my own workstation, which
is only a PII/400 with an old 4G ATA-33 drive, not a server-class
system, I can certainly understand the slower performance than the WinXP
server. But the OpenVMS Samba server figure is way out there.
I can't compare performance here with a networked Linux client, because
my workstation is the sole Linux system here.
The socket options for the Linux server are:
socket options = IPTOS_LOWDELAY TCP_NODELAY SO_SNDBUF=4096 SO_RCVBUF=4096
The socket options for the VMS server are the defaults. I don't know
how to examine those. The conf file doesn't list any.
Ben
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