FWIW:

Bruce Allen wrote:
Hi Thomas,

If I understand correctly, your NFS server is connected via a 10Gb/s link to the switch, and you've spent some effort to tune it. What sort of aggregate NFS performance are you seeing? Is it at the level of 300 or 400 MG/sec? Could you please provide a few details about the hardware in your NFS box?

Our 15 and 16 disk JackRabbit units have no trouble with this, using channel bonded gigabit (no 10GbE). We measured with 4 simultaneous IOzones being run over NFS and an inexpensive gigabit switch. No jumbo frames, the fingers never left the hands, yadda yadda yadda. Atop reported the network IO rate, dstat didn't curiously enough ... the individual adapters were correct, but it got the channel bond throughput calculation wrong (multiplied the sum of the individual adapters by 4). vmstat also returned the disk IO rate.

We were seeing a sustained 420 MB/s in this configuration. About 500 MB/s to disk (journaling overhead). Used RAID6.

FWIW we also uncovered some nasty channel bond crashes under intense loads. We were able to get it stable and repeatable, at the cost of some of the more interesting channel bond modes. These crashes didn't manifest themselves until we started pushing the channel bond hard. We needed 4 clients banging on the bonded server. 3 would not crash it. These crashes manifested themselves throughout all kernels we tried (2.6.9 through 2.6.18). Running 4 separate (non-channel bonded) ports and doing the same tests did not show this crash. The driver was fine (e1000, don't even think of trying this with a Broadcom chip/driver) and well behaved.


Cheers,
    Bruce
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