LinuxQuestions.org
Help answer threads with 0 replies.
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Distributions > Red Hat
User Name
Password
Red Hat This forum is for the discussion of Red Hat Linux.

Notices

Reply
 
Search this Thread
Old 09-30-2009, 03:48 AM   #1
ursusca
Member
 
Registered: Sep 2008
Location: Toronto, ON, Canada
Distribution: Gentoo, RHEL (Fedora, CentOS, OEL), Ubuntu, FreeBSD, Solaris 10
Posts: 170

Rep: Reputation: 34
RHEL5 running as a VMware guest


Hi All,

Red Hat Enterprise Linux 5 kernel supports four I/O schedulers:
- cfq (Completely Fair Queuing)
- deadline
- noop
- anticipatory

I read in documentation that the recommended kernel line settings for 64-bit Red Hat Enterprise Linux 5 running as a VMware guest are:

divider=10 notsc iommu=soft elevator=noop

But for single instance databases with dedicated storage the deadline scheduler is recommended. The deadline scheduler reorders I/O to optimized disk heads movement and caps maximum latency per request to prevent resource starvation for I/O intensive processes.

I have an Oracle instance on RHEL5 running as a VMware(ESX) guest with dedicated storage. What scheduler is better in my case?

I would appreciate if you could clarify this...
 
Old 09-30-2009, 07:30 PM   #2
jonesr
Member
 
Registered: Feb 2008
Location: Sacramento
Distribution: RHEL AS, mostly
Posts: 44

Rep: Reputation: 18
We have several x86_64 RHEL 5.3 systems that are Oracle servers running under ESX 3.5. All have just "divider=10 notsc". I haven't looked into iommu-- did that come from RHEL or VMware or Oracle? The docs from the different sources seem to say something different every few months, and if nothing is broken I don't obsess over trying to keep up with the latest changes.

I tried an experiment several months ago, probably on RHEL 4.6 and an earlier ESX, and I could not tell any significant difference between the performance of the different I/O scheduler options. When we moved most all of our storage to a fiber-connected SAN, the SAN controller's buffering washed out any kernel optimizations and all the schedulers gave about the same results. I leave it at the default. YMMV depending on specifics of your storage.
 
Old 10-01-2009, 12:17 AM   #3
ursusca
Member
 
Registered: Sep 2008
Location: Toronto, ON, Canada
Distribution: Gentoo, RHEL (Fedora, CentOS, OEL), Ubuntu, FreeBSD, Solaris 10
Posts: 170

Original Poster
Rep: Reputation: 34
Quote:
Originally Posted by jonesr View Post
We have several x86_64 RHEL 5.3 systems that are Oracle servers running under ESX 3.5. All have just "divider=10 notsc". I haven't looked into iommu-- did that come from RHEL or VMware or Oracle? ...
Hello,

Thank you for attention to my question. I found about it in Red Hat documentation:
Oracle 10g Server on Red Hat®
Enterprise Linux® 5
Deployment Recommendations
Version 1.2
November 2008

Can you advice me any documentation about Oracle on VMWare?

Last edited by ursusca; 10-01-2009 at 12:20 AM.
 
Old 10-01-2009, 08:11 PM   #4
jonesr
Member
 
Registered: Feb 2008
Location: Sacramento
Distribution: RHEL AS, mostly
Posts: 44

Rep: Reputation: 18
Quote:
Originally Posted by ursusca View Post
Hello,
Can you advice me any documentation about Oracle on VMWare?
I have not seen anything special for Oracle on VMware.

I'll take at iommu.-- thanks for the pointer.
 
Old 10-07-2009, 02:16 PM   #5
ursusca
Member
 
Registered: Sep 2008
Location: Toronto, ON, Canada
Distribution: Gentoo, RHEL (Fedora, CentOS, OEL), Ubuntu, FreeBSD, Solaris 10
Posts: 170

Original Poster
Rep: Reputation: 34
Quote:
Originally Posted by jonesr View Post
I have not seen anything special for Oracle on VMware.

I'll take at iommu.-- thanks for the pointer.
You are welcome. Can you tell me about a "noatime" mount parameter for ext2 and ext3 file systems. Is it really improves I\O?
 
Old 10-13-2009, 04:58 PM   #6
jonesr
Member
 
Registered: Feb 2008
Location: Sacramento
Distribution: RHEL AS, mostly
Posts: 44

Rep: Reputation: 18
Quote:
Originally Posted by ursusca View Post
...Can you tell me about a "noatime" mount parameter for ext2 and ext3 file systems. Is it really improves I\O?
noatime improves I/O by avoiding writes. When it is present the file system manager does not stamp directory and file inodes with the last time they were accessed, which saves the disk writes necessary to update those inodes.

People rarely care about the atime of an Oracle tablespace, so in those file systems this lets you give the system permission to skip that work.
 
  


Reply


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 Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Communication between Host(RHEL5) and VMware Guest OS(RHEL5) riteshanand40 Linux - Newbie 2 08-02-2009 10:52 PM
Running VMware Server on Windows XP, Guest OS is Debian. Problems! PiLLeN Linux - General 1 09-04-2006 07:58 PM
Running VMware Server on Windows XP, Guest OS is Debian. Problems! PiLLeN General 1 09-04-2006 05:10 PM
problem with running guest OS on VMware jogurt666 Linux - Software 2 10-02-2005 02:14 AM
Running Linux 8.0 Guest under Win2K with VMware IdolWild Linux - General 6 03-03-2003 02:29 AM


All times are GMT -5. The time now is 01:14 PM.

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