Disappointing ethernet performance on Xserve (2006) Leopard Server

[thornrag]

I feel my Xserve’s ethernet performance is not what it could be. What would be reasonable for a 2006 Xserve running Leopard Server?

It came up when I noticed a file transfer from an OpenSolaris server to the Xserve taking almost twice as long as from the same server to a Windows machine using the same gigabit switch.

Now I know all about differences in protocols and implementations and the influence of disk speed and all, but Activity Monitor was showing about 10MB/sec activity, which doesn’t even seem in the ballpark for gigabit ethernet.

So I tried some dd over SSH, running dd if=/dev/zero | user@xserve.local “ssh of=/dev/null” from the OpenSolaris server. Activity Monitor on the Xserve reported a peak of about 20 megabytes per second total. Hmph.

I did the same test, but with my MacBook Pro as the target. Activity Monitor there showed about 35MB/s. Not impressive, but still… better than the Xserve. Now why would that be?

Since I can’t use dd and ssh on Windows as reliably, I can’t compare the exact results, but the OpenSolaris server is capable of pushing about 85 MB/s using SMB to the Windows PC. So the Opensolaris box is capable of well more than 20MB/s.

The MTU’s on all the relevant interfaces are at standard – 1500. They’re all connected to the same switch using decent cables which I’ve swapped around. Tried different switch ports too.

TLDR: Xserve is the slowest thing on my network. What gives? How fast can other Xserves go?

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