Ted Mittelstaedt wrote:
----- Original Message ----- From: "O. Hartmann" <[EMAIL PROTECTED]>
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.


If SYNC is default how can you explain this:

[12:[EMAIL PROTECTED]:~# 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:[EMAIL PROTECTED]:~# 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.


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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