On Tue, Jan 5, 2010 at 2:05 PM, nixlists <nixmlists@gmail.com> wrote:
quoted text
> Hi.
>
> I have two machines one running 4.6, the other running a recent
> snapshot of current. tcpbench reports maximum throughput of 275 Mbit -
> that's around 34 MB/s between them over a gig-E link. What should one
> expect with an el-cheapo gig-e switch and 'em' Intel NIC and a  msk
> NIC? Is that reasonable or too slow?
>
> The 4.6 machine has a softraid mirror and can read off it at around 55
> MB/s as shown by 'dd', and the -current machine has an eSATA enclosure
> mounted async for the purpose of quickly backing up to it, that I can
> write to at around 45 MB/s as shown by 'dd'. However copying over the
> network to it - through NFS I can only get around 15 MB/s. Where is
> the bottleneck?
> How to fix??
>
> Copying with rsync over ssh is even slower due to rsync and ssh eating
> quite a bit of CPU - but that's to be expected.
>
> Thanks a bunch.
>
>

It would be best put this way - if you go for the lowest bidder, in
most cases you get what you pay for.  Your results aren't too bad
considering what's in use.

With top notch stuff (we're talking HP Procurve/Cisco Catalyst and
Intel PRO/1000+ cards here) plus tuning for Jumbo frames, you can get
to the 95MB/sec range.

And it's not just CPU usage that slows rsync over ssh - the transfer
rate is only counting the data that gets pushed through - it doesn't
cover the encrypted data, which is something like 30-40% bigger than
the original.

--
Aaron Mason - Programmer, open source addict
I've taken my software vows - for beta or for worse