Bug 800181: NFSv4 on RHEL 6.2 over six times slower than 5.7

[Allen Chen]

On 07/26/2012 03:19 PM, m.roth at 5-cent.us wrote:
> Allen Chen wrote:
>> On 07/11/2012 10:38 AM, m.roth at 5-cent.us wrote:
>>>> From: Corey Kovacs<corey.kovacs at gmail.com>
> <snip>
>>>> On Tue, Jul 10, 2012 at 8:47 PM, mark<m.roth at 5-cent.us>   wrote:
>>> <snip>
>>>>> I'll say it one more time: we found the problem on CentOS. We went to
>>>>> our test RHEL system. Updated it. Exported a directory *from* the RHEL
>>>>> box to itself, to /mnt/foo, and ran the test, and got the same results.
>>>>>
>>>>> In fact, I ran it twice today, updating the kernel in between, and
>>>>> with 6.3, it's taking a consistent 7.5 min, instead of the 6.5 we were
>>>>> getting with 6.2
>>>>> <snip>
>>>>>
>>>>>    Now, all that said and done, here are some questions for you which
>>>>> might help us figure what would help.
>>>>>> 1. What options are present on the mount? (cat /proc/mounts, thinks
>>>>>> like sync can be a problem)
>>> /scratch/foo<same_server>(rw,sync,no_wdelay)
>>>
> <snip>
>>>>>    2. What does your /etc/exports config look like on your server node
>>>>> (cat /etc/exports)
> <snip>
>>>>> Do you mean selinux auditing? As I said, doing it on the local drive
>>>>> takes seconds. Doing it from a 5.x NFS server takes about 1.5 min.
>>> Therefore,
>>>>> there's nothing that could affect it on the one server.
>> I did a quick test on my CentOS 6.2, and I don't see any slow untar.
>> Here are the steps I did:
>>
>> On server:
>> # uname -a
>> Linux backup62 2.6.32-220.el6.i686 #1 SMP Tue Dec 6 16:15:40 GMT 2011
>> i686 i686 i386 GNU/Linux
>>
>> on my desktop:
>> # uname -a
>> Linux centos62 2.6.32-220.el6.i686 #1 SMP Tue Dec 6 16:15:40 GMT 2011
>> i686 i686 i386 GNU/Linux
>> # mount -t nfs server-ip:/images /mnt
>> # time tar xvfz /mnt/hs21.tgz
>> ...
>> real    0m5.496s
>> user    0m0.438s
>> sys    0m0.176s
>>
>> # cd /mnt
>> time tar xvfz hs21.tgz
>> ...
>> real    0m20.634s
>> user    0m0.414s
>> sys    0m0.135s
>>
>> # ll hs21.tgz
>> -rw-r--r-- 1 root root 43725908 Apr  2  2008 hs21.tgz
> Allen,
>
>     what does /etc/exports read? On my system, if I have it as
>
> /scratch/foo<fwdn.hostname>(rw,sync,no_wdelay)
>
> I get the delay. Following someone's post a week or two ago, I tried
> /scratch/foo<fwdn.hostname>(rw,async,no_wdelay)
>
> and it goes at a reasonable speed. That (a)sync seems to override
> everything else. However, I'm trying to get together with my manager to
> decide if we want to use async - that's above my pay grade, and we have to
> consider that we have a fair number of users that run jobs that run for
> literally days, sometimes over a week, and loss of any data at all might
> mean false results, or having to rerun it.
>> Is there anything you can do with the DNS settings on the server side?
> DNS has nothing to do with the test case.
>
>       mark
>
# cat /etc/exports
/images 192.168.1.0/24(rw) 10.235.4.2/32(rw)

Allen