LinuxQuestions.org
Latest LQ Deal: Latest LQ Deals
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Virtualization and Cloud
User Name
Password
Linux - Virtualization and Cloud This forum is for the discussion of all topics relating to Linux Virtualization and Linux Cloud platforms. Xen, KVM, OpenVZ, VirtualBox, VMware, Linux-VServer and all other Linux Virtualization platforms are welcome. OpenStack, CloudStack, ownCloud, Cloud Foundry, Eucalyptus, Nimbus, OpenNebula and all other Linux Cloud platforms are welcome. Note that questions relating solely to non-Linux OS's should be asked in the General forum.

Notices


Reply
  Search this Thread
Old 10-01-2010, 04:10 AM   #1
shivakumargone
LQ Newbie
 
Registered: Sep 2010
Posts: 14

Rep: Reputation: 0
Allocation of CPU Cores on RHEV-H


Hi All,

Can you please explain what will happen in the following scenario:

I have 16 Cores on RHEV-H. If I create 5 VMs with 4 Cores to each then how VMs will share the Cores and what will happen if CPU load is very high(near to 95%)?

Thanks and Regards
Shiva Kumar Gone
 
Old 10-02-2010, 01:26 PM   #2
acid_kewpie
Moderator
 
Registered: Jun 2001
Location: UK
Distribution: Gentoo, RHEL, Fedora, Centos
Posts: 43,417

Rep: Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985Reputation: 1985
Well I'm not sure exactly if RHEV-H makes nay further configuration about it, but KVM will allow you to peg certain cores to certain VM's, allowing you to partition off as many cores as you want, which will then be freely contended within each cores permitted guests vms
 
Old 10-03-2010, 06:49 AM   #3
dyasny
Member
 
Registered: Dec 2007
Location: Canada
Distribution: RHEL,Fedora
Posts: 995

Rep: Reputation: 115Reputation: 115
you can always open a support ticket with RHT and ask
 
Old 10-05-2010, 10:07 PM   #4
cjcox
Member
 
Registered: Jun 2004
Posts: 307

Rep: Reputation: 42
So, you have an over commit situation. If I understand you correctly, you've created a scenario that requires more cores than what you actually have to give... as expected, performance is going to drop off dramatically (under high loads across all). Virtualization is designed to make effective use of under utilized hardware resources. It's not a miracle maker. Thus if you have 20 guests that aren't used much and a total of 16 cores, things work great if each guest uses one core.

If you have one guest that needs more resources, dedicate more to it. But IMHO, you've created a scenario that doesn't work well.... right? Or am I missing something?

Also, this problem could be worse if those aren't TRUE cores (e.g. Intel Hyperthreads).

First rule of virtualization, start guests off with the minimum resources you can give them. Then examine utilization and bump where needed.
 
Old 10-12-2010, 05:05 AM   #5
shivakumargone
LQ Newbie
 
Registered: Sep 2010
Posts: 14

Original Poster
Rep: Reputation: 0
Thanks for the reply.

My doubt got clarified. Performance is really poor when we over commit the resources.

Thanks and Regards
Shiva kumar Gone
 
  


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 On
HTML code is Off



Similar Threads
Thread Thread Starter Forum Replies Last Post
[SOLVED] AMD CPU: Athlon II or Phenom II? And how many cores? Jyde Linux - Hardware 43 10-11-2010 10:33 PM
hide cpu cores from an application thllgo Linux - Server 3 06-17-2010 04:08 AM
Disable CPU cores in RHEL3 ElectroLinux Linux - Server 1 03-31-2008 05:34 PM
Software and CPU Cores DIGITAL39 Linux - Software 8 10-10-2007 02:47 AM
how to find number of cores in CPU narensr Linux - Hardware 5 08-24-2006 01:09 PM

LinuxQuestions.org > Forums > Linux Forums > Linux - Virtualization and Cloud

All times are GMT -5. The time now is 12:08 PM.

Main Menu
Advertisement
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
Open Source Consulting | Domain Registration