LinuxQuestions.org
View the Most Wanted LQ Wiki articles.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - General
User Name
Password
Linux - General This Linux forum is for general Linux questions and discussion.
If it is Linux Related and doesn't seem to fit in any other forum then this is the place.

Notices

Reply
 
LinkBack Search this Thread
Old 10-07-2009, 10:54 PM   #1
kaz2100
Senior Member
 
Registered: Apr 2005
Location: Penguin land, with apple, no gates
Distribution: Debian testing woody(32) sarge etch lenny squeeze(+64) wheezy jessie
Posts: 1,397

Rep: Reputation: 81
Disk I/O too fast?? (SATA-2)


Hya,

While I am tuning up my Penguin (Debian, squeeze), I am confused.

Main job with this penguin is processing huge data, so I guess so so CPU intensive and disk I/O. "top" reading agrees, 40-80% user CPU, 5-10% iowait.

Next, I wanted to check whether disk i/o was a bottleneck, in this case putting data on SSD may improve performance. "iostat" reading says that ca. 180000 blocks read/sec. Now, I am lost. "tune2fs -l" says that 1 block = 4096. (mkfs says that unit is byte, not bit).
1.6E4 block_read/sec $times$ 4096 bytes/block $times$ 8 bit/byte $nearly equals$ 5.9E9 bit/sec. This exceeds SATA-2 spec (which is 300MByte/sec = 2.4E9 bit/sec), of course disk transfer rate in catalog, (1406 Mbit/sec).

What is wrong? Answer is that the block iostat refers is 512 byte as man page says!

So transfer speed is 5.9E9 bit/sec $dev$ 8 $equals$ 7.4E8 bit/sec.

If anybody else run into same question, read this thread!

Happy Penguins!
 
Old 10-08-2009, 02:57 PM   #2
H_TeXMeX_H
Guru
 
Registered: Oct 2005
Location: $RANDOM
Distribution: slackware64
Posts: 12,928
Blog Entries: 2

Rep: Reputation: 1266Reputation: 1266Reputation: 1266Reputation: 1266Reputation: 1266Reputation: 1266Reputation: 1266Reputation: 1266Reputation: 1266
Quote:
Originally Posted by kaz2100 View Post
If anybody else run into same question, read this thread!

Happy Penguins!
Well, if you want to increase the chance of that I would mark the thread as solved.
 
  


Reply

Tags
disk, iostat, speed


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Internal SATA Drive and external SATA Disk Array. bruceharbin Linux - Hardware 1 05-25-2009 12:33 AM
System collapse without kernel panic when copy file to a sata-disk or usb-disk JammyWei Linux - Embedded & Single-board computer 0 12-25-2008 08:21 PM
Ide Drive Not Seen By The Kernel With Sata Disk As Boot Disk xasanchez Linux - Newbie 3 12-27-2007 12:18 PM
swap: beginning of fast disk or beggining of second disk sl4ckw4re Slackware 4 07-19-2006 06:41 PM
Clone IDE disk to SATA disk sdem Linux - Software 1 02-16-2006 05:51 AM


All times are GMT -5. The time now is 05:13 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration