From: Adam and Christine Levin (levins@westnet.com)
Date: Thu Aug 01 2002 - 12:40:23 EDT
So we've got this brandy-nifty-new Auspex network attached monster, and
we're trying to squeeze performance out of it.
Clients are three Enterprise E450s, 2GB memory, 4x400MHz CPU, using a Sun
GigabitEthernet 2.0 adapter. Latest recommended patch cluster (105181-32)
and latest patches for the SUNWged drivers. I've got /dev/udp tweaked via
ndd (recv/xmit hiwat are 64k).
The filesystems are mirrored stripes -- no RAID 5.
So I mount the filesystem read/write and I slam data onto it using
time dd if=/dev/zero of=foo bs=1024000 count=200
(Yes, I've tried varying the block size.)
By default, NFS is TCP, and I get about 30MB/sec write (240Mbps).
Reading, I get 20MB/sec. The 20MB/sec is *per Sun machine* -- each Sun is
reading simultaneously at 20MB/sec, so the Auspex is pumping out 60MB/sec
(480Mbps). It almost seems like there's a hard receive limit or something
going on here. The read test is:
time dd if=foo of=/dev/null bs=16384
I've also tried of=/tmp/foo -- still 20MB/sec.
When I mount proto=udp, I get a hair faster write times, but about the
same. The read, however, is wonky. Measuring the transfer rate each
second, I get:
58800
222306
0
2299388
56349
80234
600234
0
500234
0
...
There are two Alteon gigabit cards in the Auspex unit on different VLANs.
The default route on the Auspex is out the 100Mbit card (the gigabit cards
are on private, non-routable VLANs, the 100Mbit card is the management
address). The primary gigabit card on the Auspex is on the same VLAN as
the gigabit cards on the Sun machines.
The switch is a Cisco 6500.
Any thoughts as to:
1) Why I can only get 20MB/sec read when writing is faster?
2) Why reading off the Auspex via UDP is wonky?
Thanks much,
-Adam
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