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Re: Slow XFS write

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On Wed, Aug 22, 2018 at 04:02:42PM +0200, Martin LEUSCH wrote:
>>what happens with
>>dd if=/dev/zero of=/var/srv/nfs/testfile bs=64k count=16k conv=fsync
>>
>>And this is direct on the server, not via NFS, right?
>>
>I've got same result as previous test.
>tests with dd command are executed directly on the server.

Can you rebuild the partition? If so, unmount it then perform the dd 
directly to the device. (of=/dev/sda2 or whatever) What's the hardware 
raid vendor? Honestly, the performance of ext4 partition is also 
horrible, just not as bad as the xfs partition. What's the hardware raid 
model? Does it have a battery backed cache? (I will guess not, because 
the test is only 1G and that should fit into most current caches?) If 
the test directly to the partition shows good performance, then it might 
be an alignment issue; try recreating the fs with `mkfs.xfs -d 
su=64k,sw=2 ...`. If the performance is the same to the raw partition 
(and still much worse than the root partition) then the partition 
alignment itself might be off--which means recreating the partitions. 
(fsck and mkfs.xfs normally handle this automatically, but that depends 
on the raid controller+driver passing the information up, and per your 
xfsinfo output, that didn't happen.)

Mike Stone

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Thread

Slow XFS write Martin LEUSCH <sce.tech@imereos.fr> - 2018-08-22 12:00 +0200
  Re: Slow XFS write Michael Stone <mstone@debian.org> - 2018-08-22 13:20 +0200
    Re: Slow XFS write Martin LEUSCH <sce.tech@imereos.fr> - 2018-08-22 14:30 +0200
      Re: Slow XFS write Michael Stone <mstone@debian.org> - 2018-08-22 15:20 +0200
        Re: Slow XFS write Martin LEUSCH <sce.tech@imereos.fr> - 2018-08-22 16:10 +0200
          Re: Slow XFS write Michael Stone <mstone@debian.org> - 2018-08-22 18:00 +0200
            Re: Slow XFS write Michael Stone <mstone@debian.org> - 2018-08-22 18:00 +0200
  Re: Slow XFS write Martin LEUSCH <sce.tech@imereos.fr> - 2018-08-22 16:20 +0200
    Re: Slow XFS write Reco <recoverym4n@gmail.com> - 2018-08-22 19:40 +0200
  Re: Slow XFS write Stefan K <shadow_7@gmx.net> - 2018-08-23 09:10 +0200
    Re: Slow XFS write Martin LEUSCH <sce.tech@imereos.fr> - 2018-08-23 11:20 +0200

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