Date: Fri, 02 Mar 2007 13:38:45 +0200 From: Cheffo <cheffo@FreeBSD-BG.org> To: Ted Mittelstaedt <tedm@toybox.placo.com> Cc: freebsd-performance@freebsd.org, "O. Hartmann" <ohartman@zedat.fu-berlin.de>, freebsd-questions@freebsd.org Subject: Re: (S)ATA performance in FBSD 6.2/7.0 Message-ID: <45E80CC5.8080607@FreeBSD-BG.org> In-Reply-To: <00c401c75caf$89ee3370$3c01a8c0@coolf89ea26645> References: <45E7F09B.7070005@zedat.fu-berlin.de> <00c401c75caf$89ee3370$3c01a8c0@coolf89ea26645>
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Hi,
Ted Mittelstaedt wrote:
> ----- Original Message -----
> From: "O. Hartmann" <ohartman@zedat.fu-berlin.de>
> To: <freebsd-performance@freebsd.org>; <freebsd-questions@freebsd.org>
> Sent: Friday, March 02, 2007 1:38 AM
> Subject: (S)ATA performance in FBSD 6.2/7.0
>
>
>> The last days I tried to figure out why some of my lab's FreeBSD boxes
>> and also mine at home seem to be outperformed by some Linux setups
>> around here and I saw something interesting.
>>
>
> blah blah blah deleted
>
>> Before digging into this problem deeper with benchmarks, could anyone
>> explain why FreeBSD reaches this 33 MB/s limit (sounds like UDMA 33
>
> man mount
>
> read section on "async"
>
> linux by default mounts async
>
> freebsd by default mounts sync
>
> you can change FBSD to async
>
> then watch your fs scramble during a power failure
>
> no big deal, it's only your data.
>
> Ted
If SYNC is default how can you explain this:
[12:58]root@hater:~# mount
/dev/ad4s3a on / (ufs, local, synchronous)
devfs on /dev (devfs, local)
/dev/ad4s3d on /tmp (ufs, local, soft-updates)
/dev/ad4s3f on /usr (ufs, local, soft-updates)
/dev/ad4s3e on /var (ufs, local, soft-updates)
[13:00]root@hater:~# cat /etc/fstab
# Device Mountpoint FStype Options Dump
Pass#
/dev/ad4s3b none swap sw 0 0
/dev/ad4s3a / ufs rw,sync 1 1
/dev/ad4s3d /tmp ufs rw 2 2
/dev/ad4s3f /usr ufs rw 2 2
/dev/ad4s3e /var ufs rw 2 2
And this is only because I manually add *sync* to my /etc/fstab.
E.g if sync is default why mount do not report that my /dev/ad4s3f on
/usr is mounted synchronous?
From what I seed in rc.X scripts mount -a -t ${mount_excludes} is used
to mount things form fstab at boot time (sync or async is not set
anywhere so we use dafault options here)
So I'm pretty sure that for type ufs async is default.
Also I do not see why sync should report different speeds for copy and
benchmark tools if they do the same thing?
Just to be sure I added to my /tmp entry async in /etc/fstab:
/dev/ad4s3d /tmp ufs rw,async 2 2
umounted and mounted again and still have:
/dev/ad4s3d on /tmp (ufs, local, soft-updates)
I think the problem is that the benchmark runs with small files and most
files are in cache that's why it shows higher speeds - try to run
bonnie++ with more and bigger files to be sure that the cache is not
enough and to be able to see the real performance of your HDDs.
PS:
Here is what I got from RAID10 4x160GB SATA2 HDDs (areca RAID)
BLAH - bonnie++ -d /var/tmp -u root -s 16g -n 256:65536:65536:16
Version 1.93c ------Sequential Output------ --Sequential Input-
--Random-
Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
--Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
/sec %CP
blah.cmotd.com 16G 159 88 54264 24 24727 12 299 94 70744 19
223.5 12
Latency 63581us 803ms 1123ms 93936us 94991us
251ms
Version 1.93c ------Sequential Create------ --------Random
Create--------
blah.cmotd.com -Create-- --Read--- -Delete-- -Create-- --Read---
-Delete--
files:max:min /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
/sec %CP
256:65536:65536/16 715 24 826 25 17321 49 733 24 51 2
6039 70
Latency 1220ms 408ms 2805ms 1189ms 692ms
2735ms
50MB/s write & 70MB/s read from 4HDDs .. so I do not know how you expect
75MB/s with single HDD.
--
Best Wishes,
Stefan Lambrev
ICQ# 24134177
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