vFrank

Essense of virtualization

  • Linkedin
  • RSS
  • Twitter
  • Home
  • About
  • Cohesity
  • PernixData
  • VCP
  • vscsistats
  • ESXTOP
  • January 16, 2021

Performance: RDM vs. VMFS

March 22, 2011 by FrankBrix 4 Comments

Last night on twitter there was a discussion about RDM vs. VMFS performance. I have always told everybody that RDM did not have an performance advantage over a VMDK file on a VMFS volume. I have refered people to the following document by VMware: Performance Characteristics of VMFS and RDM but I have never done my own testing until now 🙂

My setup is ESXi 4.1 build 260247 with 4gb fibre channel HBA connected to a SUN Storagetek 2540 SAN. I did the test on a 10GB LUN located on fibre channel disks. The test was done with Iometer on a virtual machine running Windows 2003 SP2. I performed all tests on the 10GB LUN as either: Physical RDM, Virtual RDM, Lazy Zeroed VMDK on a VMFS and Eager Zeroed VMDK on a VMFS.

I configured Iometer with settings from the unoffical storage performance thread on VMware communites and ran two tests: Maxthroughput and Real life. Here are my results:

Conclusion: VMFS and RDM have similar performance. Don’t choose RDM for performance.

Share this:

  • Facebook
  • LinkedIn
  • Twitter
  • Google
  • Print

Filed Under: Uncategorized



Vembu

Advertisement

Follow me on Twitter

My Tweets

Blogroll

  • Hazenet
  • Michael Ryom
  • Perfect Cloud
  • vTerkel

Copyright © 2021 · News Pro Theme on Genesis Framework · WordPress · Log in