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joeclark 03-15-2004 08:38 PM

NFS Performance Tuning
I am attempting to use NFS as a server on an older laptop (400MHzish) with Mandrake 8.2 with 3Com 10/100 card. The client is a LynxOS machine, appx. 200 MHz PPC. I am hoping to write a file over NFS from a process that takes a large amount of CPU time. The mount works all right with rsize & wsize set to 1024 (but not at 2048 or larger), but even at rsize=1024, NFS causes this CPU-busy process to lose data while (I assume) waiting for blocking IO calls.

It seems that this busy-ness is exacerbated if I also at the same time make frequent (= every four seconds or so) NFS FSSTAT (via statfs system calls) to determine directory free space. I suppose this is simply because the IO is further slowed down by the additional requests....

Anyone know of other ways to tweak performance? I though of the async option, but LynxOS does not have that option.

Yeah, I know the better option is probably to separate the file-writing from the process via some IPC mechanism....just wondering if there's another way.

leckie 03-16-2004 03:42 AM

dont make rsize & wsize equal to each other, have the server with a high wsize and low rsize. And have the client with a high rsize and low wsize.

Or even better use smb, i know microsoft and all but it is much better then nfs

joeclark 03-16-2004 08:08 PM

Well, if I use the defaults on both server (Linux) and client (LynxOS), the mount does not work -- tends to hang the client machine for long periods of time; when writing data to from client->server, there are a very large amount of IP reassembly ICMP errors (bad network drivers???), so I must use a client-side rsize of 1024 (that's all I've found that works). I wasn't sure that I could set the rsize and/or wsize on the server -- is that a valid /etc/exports option?

I tried Mandrake 10 today, by the way, and it suffers the same bad performance (I think it's a client problem, so that didn't really surprise me).

SMB: Yeah, would be nice. I'm not sure that LynxOS has a decent client for it...

Thanks for your reply. -- Joe

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