[Samba] Is there a buffer or cache setting in samba?

[AndyLiebman at aol.com]

Hi. 

Can anyone tell me if samba has any settings that determine how much data 
gets cached or buffered in RAM before being written to the computer's hard 
drives? 

I'm having a strange problem and I suspect that the explanation has to do 
with that kind of setting. 

I am using a Linux system (P4-3.06 Ghz, 1 GB RAM, 2.4.22 kernel, samba 
2.2.8a) to store video and audio files that can be accesssed by a group of 
Windows-based video editing systems. I got the whole system up and running a week ago 
and it was working perfectly (my storage devices, by the way, are a series of 
firewire drives arranged into a RAID 10 array) 

When I tested the system with "disk testing program" on the Windows side, I 
got a transfer rate of 22 MB/sec for a 1 GB test. And in real life, I could 
sustain a rate of at least 18 MB/second for 20 minutes over my gigabit network. 
That's what is required for my application -- digitizing uncompressed video. 

But now things have suddenly fallen apart. Yesterday I had to reinstall 
Mandrake 9.2 because I had been moving firewire and ethernet cards around to 
different PCI slots to optimize the system and I just messed things up too much. So 
I reinstalled and went back to the same card configuration I had when I got 
the 18 MB/second. And now it doesn't work. 
I know that I am using a DIFFERENT smb.conf file now compared to before. I 
don't think I have the old one that I had made with SWAT. The one I'm using 
right now is very simple and it forces a user and group name on all files written 
to the Linux share. 

Looking at a Linux monitoring program -- I believe it's called XOSVIEW -- I 
think I can see the problem. 

Yesterday when I tested the system I saw that all the RAM had to "fill up" 
completely (took about 40 seconds at 18 MB/sec) before Linux started writing to 
the hard drives. And shortly after that my Windows video program would abort, 
telling me the data wasn't getting transferred fast. 

Last week, when things were working -- and I was using the same monitoring 
program --Linux would start writing to the drives after about just a few seconds 
rather than buffering or caching so much data in RAM. And I could see in the 
monitoring program that there was more RAM free. 

There must be a setting in samba that determines how much data is cached or 
buffered in RAM before writing it to the drives. Do you know anything about 
this? 

Your advice would be very much appreciated. 

Andy Liebman