Re: strange performance issues with OS X 10.6 client

[Chuck Lever <chuck.lever@oracle.com>]

On 04/20/2010 05:21 PM, Stefan Kr=FCger wrote:
> On Mon, 19 Apr 2010, Chuck Lever wrote:
>
>> On 04/19/2010 08:21 AM, Stefan Kr=FCger wrote:
>>> On Thu, 15 Apr 2010, Stefan Kr=FCger wrote:
>>>
>>>> Hello list,
>>>>
>>>> I have some really strange nfs performance issues
>>>>
>>>> NFS server is Fedora 12, running
>>>> * kernel-2.6.32.11-99.fc12.x86_64 and
>>>> * nfs-utils-1.2.1-4.fc12.x86_64
>>>> * nfs shared /home is ext4 with default mount options
>>>>
>>>> /etc/exports:
>>>> /home   192.168.1.0/255.255.255.0(rw,sync)
>>>>
>>>> nfs and nfslock are up and running
>>>>
>>>> Nothing else touched on the server nfs-wise.
>>>>
>>>> NFS client is Mac OS X, version 10.6.3
>>>>
>>>> My /home dir is automounted on the Mac with the following mount op=
tions:
>>>> * nosuid,nodev,resvport,rdirplus,rwsize=3D1048576
>>>> (nfsv3 and tcp are default, I have also tried udp, and with and wi=
thout
>>>> rdirplus, with different read/write sizes (started with 32k, less =
for udp,
>>>> and then cranked it up to 1m to make the beachball appear less oft=
en),
>>>> but I still have issues no matter which options I chose)
>>>>
>>>> Anyway, I'm stuck now, surfing the web with Safari is a very unple=
asant
>>>> experience on nfs, beachball every now and then together with a hu=
ge amount
>>>> of network traffic (RX with 20MB/s+ peaks), not unusual to see sev=
eral
>>>> gigabytes received after some minutes browsing, XCode shows a ''Th=
e
>>>> document "SomeFile.m" could not be saved.''-error after some edits=
, Opera
>>>> hangs for minutes when closing, etc etc.
>>>>
>>>> It's horrible :(
>>>>
>>>> Another example, extracting
>>>> http://www.bignerdranch.com/solutions/Cocoa-3rd.tgz took over 3min=
!
>>>>
>>>> $ time tar xzf Cocoa-3rd.tgz
>>>> 0.169u 3.198s 5:51.10 0.9%	0+0k 1+6972io 0pf+0w
>>>> $ time rm -rf Solutions-Cocoa-3rd/
>>>> 0.014u 0.477s 0:45.59 1.0%	0+0k 1+1io 0pf+0w
>>>>
>>>> So any help or hints really appreciated
>>>
>>> So, no answers yet, but I did some more tests, i.e. I tried extract=
ing the
>>> Cocoa-3rd.tgz (2.2MB, 12MB untar'ed) on FreeBSD 8.0-REL (running in=
side
>>> VMWare though), and still it was much faster (5:51.10 vs 0:09.35) t=
han
>>> extracting on bare metal fedora12:
>>>
>>> $ time tar xfz Cocoa-3rd.tgz
>>> 0.104u 1.474s 0:09.35 16.7%	0+0k 0+4896io 0pf+0w
>>> $ time rm -rf Solutions-Cocoa-3rd
>>> 0.006u 0.160s 0:01.24 12.9%	0+0k 0+0io 0pf+0w
>>>
>>> I captured the nfs traffic with tcpdump (tcpdump -i eth1 -s 0 -w nf=
s.out
>>> host nfssrv and port 2049) on both freebsd8 (interface for freebsd =
is a bit
>>> different ofc) and fedora12 while running
>>>
>>> tar xfz Cocoa-3rd.tgz Solutions-Cocoa-3rd/02_GetStarted
>>>
>>> (which extracts just a couple of files) , you can find them here:
>>>
>>> Fedora 12 tcpdump ->   http://www.dpaste.org/5cvp/
>>> FreeBSD 8 tcpdump ->   http://www.dpaste.org/uCGX/
>>
>> The number of packets is around 1800 for the FreeBSD server and arou=
nd
>> 1940 for the Linux server.  The RPC counts you posted in a later ema=
il
>> show that Linux does more LOOKUP and ACCESS requests.  But generally=
, it
>> looks like your client is doing roughly the same amount of work in b=
oth
>> cases.
>>
>> But what catches my eye in the F12 tcpdump is that there are pauses
>> where the server reply is delayed by a few milliseconds after a SETA=
TTR
>> or COMMIT.  This looks normal, since disk writes can take a few
>> milliseconds.
>>
>> FreeBSD doesn't appear to have these pauses, so I suspect FreeBSD is
>> doing something illegal.  No NFS server can turn a SETATTR around in
>> just a few microseconds and claim that it is on permanent storage,
>> unless it has some kind of NVRAM.
>
> First of all, thanks for your answer Chuck :)
>
> there are some additional packets because the .tgz was on the same
> (nfs-mounted) dir and on a local dir during the freebsd test (so some=
 extra
> reads etc. sneaked in the linux tcpdump/nfsstat -s)
>
> Just for the record, Solaris 10u8 (UFS) extraction time is almost the=
 same as
> FreeBSDs:
>
> $ time tar xfz Cocoa-3rd.tgz
> 0.111u 1.621s 0:09.03 19.1%	0+0k 8+4966io 0pf+0w
>
> So I guess they're both cheating ;-)

Is Solaris running in a guest too?

What physical file system are you using on the Linux NFS server?

--=20
chuck[dot]lever[at]oracle[dot]com