[Samba] Reason for slow MS-DOS MS client writes

[Corey McGuire]

The low speed of writes with the MS-DOS, MS newtworking client has to do with 
the limit of MAXSENDSIZE (from TCPUTILS.INI)

By default, the value is 1024, but the maximum value is 2048.  If this value 
is not set to the same as the Samba server's SO_RCVBUF, then performence will 
suffer GREATLY.

We had a Windows system hosting Norton Ghost images, but it took a dive, and 
our company has been timidly interested in using Linux in IS areas because we 
are broke for the first time in 30 years.

For the most part, our Linux Ghost server was a huge success, and it out 
performed all Windows systems, some that are worth 4k+, and it cost us 
nothing.

There was one area it sucked, and I mean REALLY sucked!

When we wrote images at 10mbit, the Samba box was transfering at a pitiful 
7MB/minute!  And it wasn't just Ghost.  We made a 100MB Ramdisk, filled it 
with garbage, and pushed it up to the server.  It took roughly 15 minutes!  
Pushing it to a Windows box took a little less than 2.

We were happy enough with the performence otherwise, and Windows to Samba 
speeds were outstanding, but I didn't give up.  I didn't want a single black 
mark on my project.

Previously, I had set MAXSENDSIZE to 8192, which did match my Samba server at 
the time.  I STFW'd every setting on our DOS floppy and finally found that 
MAXSENDSIZE had a hard limit of 2048, and if it did not understand a value 
(like 8192) it defaulted to 1024!

Want a little math?  8192/1024=8.  ~2minutes*8=~15minutes.

Lights flashed, clouds parted, angels sung, and somewhere, a PFY scored with 
a Super Model.

We are now transfering at up to 67MB/minute at 10mbit, and with one to four 
systems on 100mbit, we are hitting the server with 130MB/minute each!  That's 
roughly 69mbit (enhanced by compression) and if networking would light up a 
few more 10/100 ports to our lab, I bet we could add another system or two 
and still transfer at that speed.

Needless to say, we are very happy with our samba server, and with this 
opensource victory at our company, we've already been authorized to replace 
all print servers at our company with a single Samba server per subnet 
(roughly 40.)

Total savings?  For software alone, possibly up to $120,000!

I wonder if they'll give it to me as a Christmas bonus?  Something tells me 
no.

Anyway, I hope this helps.  Enjoy!

PS, here is the Froppy!

http://www.coreyfro.com/~coreyfro/froppy-1.6.1-ex.zip

This is our "all network drivers in one DOS boot floppy" floppy.