Re: Strange IO performance with UFS

Hi,

> > I'm doing some tests on IO performance using fio, and I've found
> > something weird when using UFS and large files. I have the following
> > very simple sequential fio workload:

System:
FreeBSD ox 10.0-RELEASE-p6 FreeBSD 10.0-RELEASE-p6 #0: Tue Jun 24 07:47:37 =
UTC 2014     =

[e-mail]:/usr/obj/usr/src/sys/GENERIC  amd64


1. Seq Write to 1 file, 10GB size, single writer, block 4k, UFS2:

I tried to write seq using a single writer using an IOSIZE similar to your =
example, 10
GB to a 14TB Hdw RAID 10 LSI device using fio 2.1.9 under FreeBSD 10.0. =


Result:
Run status group 0 (all jobs):
  WRITE: io=3D10240MB, aggrb=3D460993KB/s, minb=3D460993KB/s, maxb=3D460993=
KB/s, =

  mint=3D22746msec, maxt=3D22746msec


2. Seq Write to 2500 files, each file 5MB size, multiple writers, UFS2:

Result:
Run status group 0 (all jobs):
  WRITE: io=3D12500MB, aggrb=3D167429KB/s, minb=3D334KB/s, maxb=3D9968KB/s, =

  mint=3D2568msec, maxt=3D76450msec

Questions:

 - where are you writing, what storage: hdw / sfw RAID ?
 - are you using time based fio tests ? =


For fun I can share with you some results we been doing between FreeBSD10 a=
md64 (f10) =

and Debian7 amd64 (d7) using LSI HDW RAID 10. We don't use time based fio b=
ut rather =

we measure how fast we can send once the IOSIZE and measure the elapsed tim=
e. =

This proofed to be more accurate and return more sane results than actually=
 keeping =

fio running for 15 or 30minutes.

Id=A0 =A0 =A0 Test_Name=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 Throughput=A0 =
=A0 =A0 Utilization=A0 =A0 =A0 Idle
1=A0 =A0 =A0  f10.raid10.4k.2500=A0 =A0 =A0 =A0 23 MB/s=A0 =A0 =A0 =A0 =A0 =
 8%=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 92%
2=A0 =A0 =A0  f10.raid10.4k.5000=A0 =A0 =A0 =A0 18 MB/s=A0 =A0 =A0 =A0 =A0 =
 9%=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 91%
3=A0 =A0 =A0  f10.raid10.64k.2500=A0 =A0 =A0 215 MB/s=A0 =A0 =A0 =A0 22%=A0=
 =A0 =A0 =A0 =A0 =A0 =A0 78%
4=A0 =A0 =A0  f10.raid10.64k.5000=A0 =A0 =A0 162 MB/s=A0 =A0 =A0 =A0 18%=A0=
 =A0 =A0 =A0 =A0 =A0 =A0 82%

=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=
 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0  idle=A0 =A0 iowait
5=A0 =A0 =A0  d7.raid10.4k.2500=A0 =A0 =A0 =A0  29 MB/s=A0 =A0 =A0 =A0 =A0 =
 2%=A0 =A0 =A0 =A0 =A0 65.08 + 32.93
6=A0 =A0 =A0  d7.raid10.4k.5000=A0 =A0 =A0 =A0  29 MB/s=A0 =A0 =A0 =A0 =A0 =
 3%=A0 =A0 =A0 =A0 =A0 53.68 + 43.79
7=A0 =A0 =A0  d7.raid10.64k.2500=A0 =A0 =A0  297 MB/s=A0 =A0 =A0 =A0 3%=A0 =
=A0 =A0 =A0 =A0 56.44 + 41.11
8=A0 =A0 =A0  d7.raid10.64k.5000=A0 =A0 =A0  182 MB/s=A0 =A0 =A0 =A0 4%=A0 =
=A0 =A0 =A0 =A0 12.85 + 83.85



-- =

Stefan Parvu <[e-mail]>
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