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Date:      Sat, 20 Oct 2012 21:58:03 +0300
From:      Nikolay Denev <ndenev@gmail.com>
To:        "freebsd-hackers@freebsd.org Hackers" <freebsd-hackers@freebsd.org>
Cc:        Rick Macklem <rmacklem@uoguelph.ca>, Ivan Voras <ivoras@freebsd.org>
Subject:   Re: NFS server bottlenecks
Message-ID:  <BD7A192B-6208-4560-A955-A4B3C3563E5F@gmail.com>
In-Reply-To: <C10B14C4-943E-47CC-B6A7-4596A2D11D73@gmail.com>
References:  <937460294.2185822.1350093954059.JavaMail.root@erie.cs.uoguelph.ca> <302BF685-4B9D-49C8-8000-8D0F6540C8F7@gmail.com> <k5gtdh$nc0$1@ger.gmane.org> <0857D79A-6276-433F-9603-D52125CF190F@gmail.com> <CAF-QHFUU0hhtRNK1_p9zks2w%2Be22bfWOtv%2BXaqgFqTiURcJBbQ@mail.gmail.com> <6DAAB1E6-4AC7-4B08-8CAD-0D8584D039DE@gmail.com> <23D7CB3A-BD66-427E-A7F5-6C9D3890EE1B@gmail.com> <CAF-QHFWY0drcrUpo7GGD1zQNSDWsEeB_LHAjEbUKrX2ovQHNxw@mail.gmail.com> <C10B14C4-943E-47CC-B6A7-4596A2D11D73@gmail.com>

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On Oct 20, 2012, at 4:00 PM, Nikolay Denev <ndenev@gmail.com> wrote:

>=20
> On Oct 20, 2012, at 3:11 PM, Ivan Voras <ivoras@freebsd.org> wrote:
>=20
>> On 20 October 2012 13:42, Nikolay Denev <ndenev@gmail.com> wrote:
>>=20
>>> Here are the results from testing both patches : =
http://home.totalterror.net/freebsd/nfstest/results.html
>>> Both tests ran for about 14 hours ( a bit too much, but I wanted to =
compare different zfs recordsize settings ),
>>> and were done first after a fresh reboot.
>>> The only noticeable difference seems to be much more context =
switches with Ivan's patch.
>>=20
>> Thank you very much for your extensive testing!
>>=20
>> I don't know how to interpret the rise in context switches; as this =
is
>> kernel code, I'd expect no context switches. I hope someone else can
>> explain.
>>=20
>> But, you have also shown that my patch doesn't do any better than
>> Rick's even on a fairly large configuration, so I don't think there's
>> value in adding the extra complexity, and Rick knows NFS much better
>> than I do.
>>=20
>> But there are a few things other than that I'm interested in: like =
why
>> does your load average spike almost to 20-ties, and how come that =
with
>> 24 drives in RAID-10 you only push through 600 MBit/s through the 10
>> GBit/s Ethernet. Have you tested your drive setup locally (AESNI
>> shouldn't be a bottleneck, you should be able to encrypt well into
>> Gbyte/s range) and the network?
>>=20
>> If you have the time, could you repeat the tests but with a recent
>> Samba server and a CIFS mount on the client side? This is probably =
not
>> important, but I'm just curious of how would it perform on your
>> machine.
>=20
> The first iozone local run finished, I'll paste just the result here, =
and also the same test over NFS for comparison:
> (This is iozone doing 8k sized IO ops, on ZFS dataset with =
recordsize=3D8k)
>=20
> NFS:
>                                                            random  =
random    bkwd   record   stride                                  =20
>              KB  reclen   write rewrite    read    reread    read   =
write    read  rewrite     read                                  =20
>        33554432       8    4973    5522     2930     2906    2908    =
3886                                         =20
>=20
> Local:
>                                                            random  =
random    bkwd   record   stride                                  =20
>              KB  reclen   write rewrite    read    reread    read   =
write    read  rewrite     read                                  =20
>        33554432       8   34740   41390   135442   142534   24992   =
12493                                         =20
>=20
>=20
> P.S.: I forgot to mention that the network is with 9K mtu.


Here are the full results of the test on the local fs :

http://home.totalterror.net/freebsd/nfstest/local_fs/

I'm now running the same test on NFS mount over the loopback interface =
on the NFS server machine.




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