Re: [nfsv4]nfs client bug

[Ben Greear <greearb@candelatech.com>]

On 06/30/2011 09:26 AM, Andy Adamson wrote:
>
> On Jun 30, 2011, at 11:52 AM, quanli gui wrote:
>
>> Thanks for your tips. I will try to test by using the tips.
>>
>> But I have a question about the nfsv4 performace indeed because of the
>> nfsv4 code, that is because the nfsv4 client code, the performace I
>> tested is slow. Do you have some test result about the nfsv4
>> performance?
>
>
> I'm just beginning testing NFSv4.0 Linux client to Linux server.  Both are Fedora 13 with the 3.0-rc1 kernel and 10G interfaces.
>
> I'm getting ~ 5Gb/sec READs with iperf and ~3.5Gb/sec READs with NFSv4.0 using iozone. Much more testing/tuning to do.

We've almost saturated two 10G links (about 17Gbps total) using older (maybe 2.6.34 or so) kernels with Linux clients and
Linux servers.  We use a RAM FS on the server side to make sure disk access isn't a problem,
and fast 10G NICs with TCP offload enabled (Intel 82599, 5GT/s pci-e bus).

We haven't benchmarked this particular setup lately...

Thanks,
Ben

>
> -->Andy
>>
>> On Thu, Jun 30, 2011 at 10:24 PM, Trond Myklebust
>> <Trond.Myklebust@netapp.com>  wrote:
>>> On Thu, 2011-06-30 at 09:36 -0400, Andy Adamson wrote:
>>>> On Jun 29, 2011, at 10:32 PM, quanli gui wrote:
>>>>
>>>>> When I use the iperf tools for one client to 4 ds, the network
>>>>> throughput is 890MB/S. It reflect that it is indeed 10GE non-blocking.
>>>>>
>>>>> a. about block size, I use bs=1M when I use dd
>>>>> b. we indeed use the tcp (doesn't the nfsv4 use the tcp defaultly?)
>>>>> c. the jumbo frames is what? how set mtu automatically?
>>>>>
>>>>> Brian, do you have some more tips?
>>>>
>>>> 1) Set the mtu on both the client and the server 10G interface. Sometimes 9000 is too high. My setup uses 8000.
>>>> To set MTU on interface eth0.
>>>>
>>>> % ifconfig eth0 mtu 9000
>>>>
>>>> iperf will report the MTU of the full path between client and server - use it to verify the MTU of the connection.
>>>>
>>>> 2) Increase the # of rpc_slots on the client.
>>>> % echo 128>  /proc/sys/sunrpc/tcp_slot_table_entries
>>>>
>>>> 3) Increase the # of server threads
>>>>
>>>> % echo 128>  /proc/fs/nfsd/threads
>>>> % service nfs restart
>>>>
>>>> 4) Ensure the TCP buffers on both the client and the server are large enough for the TCP window.
>>>> Calculate the required buffer size by pinging the server from the client with the MTU packet size and multiply the round trip time by the interface capacity
>>>>
>>>> % ping -s 9000 server  - say 108 ms average
>>>>
>>>> 10Gbits/sec = 1,250,000,000 Bytes/sec * .108 sec = 135,000,000 bytes
>>>>
>>>> Use this number to set the following:
>>>> sysctl -w net.core.rmem_max = 135000000
>>>> sysctl -w net.core.wmem_max 135000000
>>>> sysctl -w "net.ipv4.tcp_rmem<first number unchaged>  <second unchanged>  135000000"
>>>> sysctl net.ipv4.tcp_wmem<first number unchaged>  <second unchanged>  135000000"
>>>>
>>>> 5) mount with rsize=131072,wsize=131072
>>>
>>> 6) Note that NFS always guarantees that the file is _on_disk_ after
>>> close(), so if you are using 'dd' to test, then you should be using the
>>> 'conv=fsync' flag (i.e 'dd if=/dev/zero of=test count=20k conv=fsync')
>>> in order to obtain a fair comparison between the NFS and local disk
>>> performance. Otherwise, you are comparing NFS and local _pagecache_
>>> performance.
>>>
>>> Trond
>>> --
>>> Trond Myklebust
>>> Linux NFS client maintainer
>>>
>>> NetApp
>>> Trond.Myklebust@netapp.com
>>> www.netapp.com
>>>
>>>
>
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-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com