serious networking (em) performance (ggate and NFS) problem

[Chuck Swiger]

Emanuel Strobl wrote:
[ ... ]
> No, because I observed similar bad performance with my fileserver which is 
> almost the same HW and it's em (Intel GbE) is connected to the local 
> 100baseTX segment.

Can you mention a little more about your hardware, or perhaps put a dmesg on a 
website somewhere?  If you don't have PCI-E hardware, especially if you are 
using classic 32-bit/33MHz PCI rather than a GbE adaptor via your mainboard's 
chipset, you're going to be limited by PCI bus throughput.

[I'd still expect you to be going faster if this was the case, however.]

Also, have you done any tuning of NMBCLUSTERS or the net.inet sysctls?

> I explicitly avoided to go via any switch/hub to eliminate further problems.
> I wonder if anybody has ever been able to transfer more than 17MB/s via IP 
> anyway?

Sure.  I've got a pair of Apple Xserves in a rack which got ~90 MB/s FTP for 
five ~600MB CD-ROM ISO images via a 3com gigabit switch.

The machine doing the writing was using a four-disk RAID-10 setup via the 
internal SATA-150 drive bays, but I paused between each transfer so some of 
that transfer rate may be due to stuff in RAM but not yet flushed to disk, so 
take that number cum grano salis.

> I need this performance for mirroring via ggate, so I'm thinking about fwe (IP 
> over Firewire).
> Perhaps somebody has tried this already? If fwe gives reasonable transferrates 
> I guess the perfomance problem won't be found in ethernet but in IP.

Well, I think Firewire is great and FreeBSD seems to have a very good 
implementation, so this might well be a reasonable alternative path.  That 
being said, gigabit ethernet ought to do as well or better than Firewire if 
you can resolve this performance issue.

-- 
-Chuck