Unless doing jumbo frames (or maybe a TOE card) you are not going to see more than about 75MB/s per TCP gig connection (with jumbo frames I've seen north of 90MB/s).  So, 75x4 ~300 MB/s for 4 ports.  However, I don't think the head will push that much - a bit over 200MB/s for large sequential read is what it's rated at.

-----Original Message-----
From:   owner-toasters@mathworks.com on behalf of Max Reid
Sent:   Mon 3/19/2007 11:10 AM
To:     k.weber@science-computing.de
Cc:     toasters@mathworks.com
Subject:        Re: Throughput on 3020

> Hello,
>
> this is my first posting to this list.
>
> A customer of us has a NetApp 3020 with 3 S-ATA shelfes each filled with
> 500 GB disks.
> He has a trunked 2*1 GBit network connection.


So with the Etherchannel or 802.3ad, he has a maximum throughput potential
of about 200MB/s. (2Gbps).  Do I understand this correctly?

Which load sharing method is the customer using on the port channel?

> He has 3 volumes, each volume resides on a different aggregate built from
> the disks of one shelf each.
>
> Via NFS he gets a perfomrance of sustained 60 MB per second with large and
> small files.
> Only one connection used during the test, no aditional traffic on the
> system and network segment.
> He expected the performance to be "much" better.


What is he doing to test? Copy files (Local disk might be bottleneck) dd?
iozone? 60MB sustained is pretty good for a single GbE connection, and my
initial guess is that his server is doing the best it can, but probably
won't go any faster with a single NIC.

  If he really wanted to tax the filer, have him use two load generators
instead of one.  If the etherchannel / link aggregation is setup in the
typical fashion, he won't see higher throughput unless he uses two
client machines.

Regards,
Max