Terrible NFS4 performance: FreeBSD 9.1 + ZFS + AWS EC2

[Berend de Boer]

>>>>> "Daniel" == Daniel Kalchev <daniel at digsys.bg> writes:

    Daniel> Could you please actually post a diagram of your setup,
    Daniel> with all the components, including the "low spec Linux
    Daniel> server". Do not forget the RTT (ping) between these
    Daniel> hosts. If you have made any network tuning too.

To be honest, I think that's of little use. I have no impact on where
my server is placed in the AWS data centre, nor what other load (cpu
or i/o) is also taking place on these boxes.

So having approximate values (I'm posting factors of 2 or 4) is the
only useful strategy.

As you can see I'm not talking about 5% differences here, only about
200% (or 2000%!!!) differences.

Pings within an AWS data centre are similar, let's say about
0.450ms. But have a reasonable range.

Unless you know AWS I think it's no use posting hardware specs (there
are none). The Linux box is a c1.medium, the FreeBSD is an
m1.large. FreeBSD is EBS optimised (but disks are not).


    Daniel> Networking protocols like NFS are heavily influenced by
    Daniel> factors like RTT.  An "underpowered" box that is "nearby"
    Daniel> (has lover RTT) usually performs much better than a
    Daniel> "powerful box" with larger RTT and other network
    Daniel> bottlenecks.

I fully agree with that.


    Daniel> Unfortunately, AWS is far from perfect hardware emulation
    Daniel> and there might be other layers that intervene with the
    Daniel> NFS protocol.

Exactly right. Given that we are talking factors of difference here I
think the hardware in this case does not matter. The problem is in the
software.

--
All the best,

Berend de Boer


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