Very nice write up and useful information, thanks!

On Wed, 17 Oct 2007, Peters, Devon C wrote:

> Since I've seen a little bit of talk about 10GbE on here in the past I
> figured I'd share some of my experiences...
>
> I've recently been testing some of Sun's dual-port 10GbE NICs on some
> small T2000's (1Ghz, 4-core).  I'm only using a single port on each
> card, and the servers are currently directly connected to each other
> (waiting for my network team to get switches and fibre in place).
>
> So far, I've been able to drive throughput between these two systems to
> about 7500Mbit/sec using iperf.  When the throughput gets this high, all
> the cores/threads on the receiving T2000 become saturated and TCP
> retransmits start climbing, but both systems remain quite responsive.
> Since these are only 4-core T2000's, I would guess that the 6 or 8-core
> T2000's (especially with 1.2Ghz or 1.4Ghz processors) should be capable
> of more throughput, possibly near line speed.
>
> The down side achieving this high of throughput is that it requires lots
> of data streams.  When transmitting with a single data stream, the most
> throughput I've gotten is about 1500Mbit/sec.  I only got up to
> 7500Mbit/s when using 64 data streams...  Also, the biggest gains seem
> to be in the jump from 1 to 8 data streams;  with 8 streams I was able
> to get throughput up to 6500Mbit/sec.
>
> Our goal for 10GbE, is to be able to restore data from tape at a speed
> of at least 2400Mbit/sec (300MB/sec).  We have large daily backups
> (3-4TB) that we would like to be able to restore (not backup) in a
> reasonable amount of time.  These restores are used to refresh our test
> and development environments with current data.  The actual backups are
> done with array based snapshots (HDS ShadowCopy), which then get mounted
> and backed up by a dedicated media server (6-core T2000).  We're
> currently getting about 650MB/sec of throughput with the backups (9
> streams on 3 LTO3 tape drives - MPX=3 and it's very compressible data).
>
> Going off my iperf results, the restoring this data using 9 streams
> should get us well over 2400Mbit/sec.  But - we haven't installed the
> cards on our media servers yet, so I have yet to see what the actual
> performanee of netbackup and LTO3 over 10GbE is.  I'm hopeful it'll be
> close to the iperf results, but if it doesn't meet the goal then we'll
> be looking at other options.
>
> --
> Devon Peters
>
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