Re: [MooseFS-Users] question about mfs reading speed slower than writing speed???

[Aleksander W. <ale...@mo...>]

Hi Peter

Which version of MooseFS are you using?

Can you tell something more about your topology - configuration?
Is your MooseFS components are in the same LAN ?
Can you check latency between all MooseFS components?


Best regards
Aleksander Wieliczko
Technical Support Engineer
MooseFS.com <moosefs.com>


On 12.04.2015 09:52, Peter wrote:
> Hi moosefs team,
>
> Recently, I setup a moosefs filesystem.
> with the following topology:
>
> Master server: 1
> Mesta logger server: 1
> chunkserver: 3
>
> and each file will keep 3 copy.
>
> base in this topology, I have run some test:
>
> *and I find that write data to the mfs file system is much faster than
> the reading speed, this test result is confusing me. can you guys
> explain a little bit this for me?*
>
>
> all the test file are the same size
> /mnt/mfs --> moosefs file system.
> /data  --> local disk 
> ---------------------------------------------------------------------------------------------
>
> [root@TENCENT64 /mnt/mfs]# time cp 111.iso /mnt/mfs/
> cp: cannot stat `111.iso': No such file or directory
>
> real    0m0.002s
> user    0m0.000s
> sys     0m0.000s
> [root@TENCENT64 /mnt/mfs]# time cp /data/111.iso /mnt/mfs/
>
> real    0m5.065s
> user    0m0.000s
> sys     0m0.316s
> [root@TENCENT64 /mnt/mfs]# time cp 555.iso /data/
>
> real    0m11.156s
> user    0m0.000s
> sys     0m0.780s
> [root@TENCENT64 /mnt/mfs]# ^C
> [root@TENCENT64 /mnt/mfs]# time cp 666.iso /data
>
> real    0m11.165s
> user    0m0.004s
> sys     0m0.864s
> [root@TENCENT64 /mnt/mfs]# time cp /data/555.iso /mnt/mfs/555-new.iso
>
> real    0m5.045s
> user    0m0.000s
> sys     0m0.300s
> [root@TENCENT64 /mnt/mfs]# ll -h
> total 3.0G
> -rw-r--r-- 1 root root 500M Apr 12 14:36 111.iso
> -rw-r--r-- 1 root root 500M Apr 12 15:33 555-new.iso
> -rw-r--r-- 1 root root 500M Apr 11 01:43 555.iso
> -rw-r--r-- 1 root root 500M Apr 11 01:46 666.iso
> -rw-r--r-- 1 root root 500M Apr 11 01:06 aaa.iso
> -rw-r--r-- 1 root root 500M Apr 11 01:39 bbb.iso
>
>
> also, i use another client server to run the test , (the client server
> in other city)
>
> we can see, the read speed is much more slow than the writing speed.
>
> [root@Tencent-SNG /mnt/mfs]# time cp 111.iso /data/
>
> real    0m44.736s
> user    0m0.005s
> sys     0m1.299s
> [root@Tencent-SNG /mnt/mfs]# time cp /data/222.iso ./
>
> [root@Tencent-SNG /data]# time cp 333.iso /mnt/mfs/333-new.iso
>
> real    0m12.432s
> user    0m0.008s
> sys     0m0.614s
>
> Also, in case there is some kernel or linux version problem, 
> I setup the moosefs master in centos 6.3 and centos 7.0.
> still have the same problem.
>
> I also search the internet , and find that, the other also have the
> same problem.
>
> Other people's performance test data:
> Block size 1M Filesize20G
> Client1 write：68.4MB/s  read：25.3MB/s
> Client2 write：67.5MB/s  read：24.7MB/s
>
>
>
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