NFS vs communications meduim (was slashes, then NFS devices)

David Burren [Athos] david at bacchus.esa.oz.au
Tue Mar 19 09:10:18 AEST 1991


In <2028 at bacchus.esa.oz.au> I wrote:

>In <11030 at dog.ee.lbl.gov> torek at elf.ee.lbl.gov (Chris Torek) writes:

>>The bandwidth of your standard, boring old Ethernet is 10 Mb/s or 1.2
>>MB/s.

>Say what?  If you can get over 1 Mb/s out of an Ethernet I'd like to hear
>about it.

Bruce Barnett @ GE kindly sent me a copy of a posting to comp.protocols.tcp-ip
by Van Jacobson in October 1988.

In it he described tests using Sun-3s with two types of Ethernet controller:
a Lance and an i82586.  The LANCE came out best, with throughputs up to
1000 kbytes/sec, while the Intel part peaked out at 720 kbytes/sec.

I stand corrected in what Ethernet can do :-)  Mind you, unfortunately I
suspect that this optimised code is still absent in many shipped systems.
I do not know if the Sonys here incorporate the Van Jacobson TCP.


So, Ethernet being capable (depending on controller and software) of
sustaining throughputs similar to modern asynch SCSI-1 setups, we're back
to the distinct performance difference between local disks and NFS.
Eg. in my previous posting: fs performance (block reads) on:
	SCSI	600 kb/s
	NFS	270 kb/s

Not that I've added all that much to the discussion :-(  Back to the experts...

- David B.



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