What factors make a difference when transfering large files to and from samba shares.

I've been testing some equipment and the results were not as I expected. I have 2 samba servers, one is a very simple Crux test install with a customized kernel for the hardware and samba compiled from source with optimizations for my needs. The server is a 950Mhz CPU with 256M Ram and a Netgear Network card.

The other system is RedHat 9 with a binary install of Samba 2.2 and a generic 2.4 kernel. It is on a 450Mhz CPU with 768M Ram.

When transfering large files (CD ISO's) , the old 450Mhz, RedHat 9 with samba 2.2 transfers the file in half the time of the Crux machine. Is there any item that stands out as to why the old 450Mhz machine is faster than the 950Mhz. Is it the extra RAM, the older version of Samba, or something else? Any help would be appreciated.

buffer sizes are the normal culprits for samba speeds. you might benefit from modify the socket options in the server config file, smb.conf

Thanks for the quick reply. The last three options were not in the Crux smb.conf, so I did add them as written. Unfortunately, the transfer time was the same over several attempts, plus or minus a few seconds.

Did you do a (service smb restart) after making changes?

the buffer sizes for both directions are worth playing with a bit, try changing them from 8k to 16k

Yes, I reloaded the conf file.

Here is a new twist. I've also been testing different aspects of FreeBSD and Fedora Core 2 with this same machine. I plugged in the Fedora Core 2 hard drive into the 950Mhz machine with a generic binary install of Samba 3.0.7 and a custom kernel. It was faster than both by about 15% as I would have suspected the first time. I guess I've missed something in the Crux setup.

Not just to throw another variable it could be the PCI bus or the Actual ethernet card it self. Cheap ethernet cards always peform bad. With windows you can use a $20.00 card, but with linux you should buy a card made for a server. The processing seems to be faster in my experience.

It isn't the hard disk that is faster?
Or maybe a DMA setting?

The Crux install is on an older hard drive, but doesn't the 2.6 kernel optimize DMA settings automatically? I thought it did , but I could be wrong

It might, but you could still experience performance differences.
I had an IBM 40GB 7200rpm disk. Recently I bought a new one 120GB Seagate 7200rpm (8MB cache).
This disc tramsports at nearly twice the speed.

Factors in speed of hard disks, among others: Rotation speed, Access time, Cache amount.