Re: Fwd: Re: Fedora27: NFS v4 terrible write performance, is async working

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On 01/29/2018 12:42 PM, Steven Whitehouse wrote:
> 
> 
> 
> -------- Forwarded Message --------
> Subject: 	Re: Fedora27: NFS v4 terrible write performance, is async working
> Date: 	Sun, 28 Jan 2018 21:17:02 +0000
> From: 	Terry Barnaby <terry1@xxxxxxxxxxx>
> To: 	Steven Whitehouse <swhiteho@xxxxxxxxxx>, Development discussions related to Fedora <devel@xxxxxxxxxxxxxxxxxxxxxxx>, Terry Barnaby <terry1@xxxxxxxxxxx>
> CC: 	Steve Dickson <steved@xxxxxxxxxx>, Benjamin Coddington <bcodding@xxxxxxxxxx>
> 
> 
> 
> On 28/01/18 14:38, Steven Whitehouse wrote:
>> Hi,
>>
>>
>> On 28/01/18 07:48, Terry Barnaby wrote:
>>> When doing a tar -xzf ... of a big source tar on an NFSv4 file system 
>>> the time taken is huge. I am seeing an overall data rate of about 1 
>>> MByte per second across the network interface. If I copy a single 
>>> large file I see a network data rate of about 110 MBytes/sec which is 
>>> about the limit of the Gigabit Ethernet interface I am using.
>>>
>>> Now, in the past I have used the NFS "async" mount option to help 
>>> with write speed (lots of small files in the case of an untar of a 
>>> set of source files).
>>>
>>> However, this does not seem to speed this up in Fedora27 and also I 
>>> don't see the "async" option listed when I run the "mount" command. 
>>> When I use the "sync" option it does show up in the "mount" list.
>>>
>>> The question is, is the "async" option actually working with NFS v4 
>>> in Fedora27 ?
No. Its something left over from v3 that allowed servers to be unsafe.
With v4, the protocol defines stableness of the writes.

>>> _______________________________________________
>>
>> What server is in use? Is that Linux too? Also, is this v4.0 or v4.1? 
>> I've copied in some of the NFS team who should be able to assist,
>>
>> Steve.
> 
> Thanks for the reply.
> 
> Server is a Fedora27 as well. vers=4.2 the default. Same issue at other 
> sites with Fedora27.
> 
> Server export: "/data *.kingnet(rw,async,fsid=17)"
> 
> Client fstab: "king.kingnet:/data /data nfs async,nocto 0 0"
> 
> Client mount: "king.kingnet:/data on /data type nfs4 
> (rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,hard,nocto,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.202.2,local_lock=none,addr=192.168.202.1)"
> 
> 
This looks normal except for setting fsid=17...

The best way to debug this is to open up a bugzilla report
and attached a (compressed) wireshark network trace to see 
what is happening on the wire... The entire tar is not needed
just a good chunk...

steved.
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