[NCLUG] measuring LAN connection speed

[Mike Loseke]

Thus spake Tkil:
> 
> if you're using NFS to share the disk, this technique should work.
> i'd be mildly surprised if NFS can squeeze out the same throughput of
> TCP over the same network, though.

 NFS isn't as bad now as it's reputation claims, even using TCP. I've been
troubleshooting a site's poor NFS performance and using mine as a
comparison (to show them just how bad their's is) recently. Here's the
times and speeds for a 500MB file transfer across the "good" production
network:

Method              rate                 time
------------------  -------------------  -------------
Using rcp           9,892    Kbytes/sec  53.05 seconds
Using ftp           9,532.64 Kbytes/sec  54 seconds
Using NFS (v3/TCP)  9,439    Kbytes/sec  55.54 seconds

 These were done from one production machine to another, like, production
machine with a normal workload going on concurrently on both. I also ran
these same tests on a couple less loaded machines resulting in NFS times
like 44.50 seconds (~11,781K/sec). These are all 100Mbit full-duplex
switched connections using NFSv3/TCP with read/write sizes of 32K.

 So NFS ain't so bad. Sure, it still blocks at times and nobody likes
stale filehandles, but those situations really only occur when the remote
machine is down or misconfigured.

-- 
   Mike Loseke    | If at first you don't succeed,
 mike at verinet.com | increase the amperage.