VirtualBox | SATA vs SCSI

Recently I tried to build a cloned instance of our production instance over VirtualBox for some emergency issues faced by our inventory module. As this instance was supposed to be only accessed by me, I opted to use my desktop machine for the same. Throughout the last many years I built my own machines, choosing the best available hardware at the time of building them. My current desktop configuration is like following

i7 processor, 16GB memory, 2x1TB 7200 RPM HDD, 2x2TB 5200 RPM HDD, 1x500GB HDD for the OS (Windows 8.1 64Bit)

and throughout the years I built dozens of Virtual Machines using Oracle VirtualBox, mainly for testing un-certified Oracle & other products in a sand-boxed environment, against the crippled VMplayer, VirtualBox’s unrestricted interface supported almost everything I needed from a virtual environment.

So I built my R12 instance, that is around 600GB roughly in size with almost 4.5-5 years of business data, media etc. The following resources were dedicated for the fresh VM

  • 4 processors
  • 10GB memory
  • 40GB fixed size SATA VDI for the Operating System (I used both OEL 5 & OEL 7 64bit)
  • 1.2TB fixed size SATA VDI for the instance files
  • A dedicated D-Link 10/100MB NIC

Once the instance came online, I removed, cancelled all the scheduled concurrent programs, changed the database level parameters like job_queue_processes etc, however the lag experienced throughout the access attempts remained the same. Sometimes the HTML pages took 5-6 minutes to open, forms based modules took 8-10 minutes to open and timeouts were happening, frustrating me to the most possible levels

That is when I decided to give VMPlayer a try, I converted the existing VDI for the OS as vmdk and created a fresh 850 fixed size vmdk for the instance files and attached the same as SCSI to the VM. Did the complete clone process and to my utter surprise, the login page loaded within a minutes once after the instance was started!

This lead me to do various attempts with the fresh instance, I was able to shutdown the instance much faster, forms were opening faster, though LOVs having more than thousands of items were taking more time than anticipated

Once again, I created another fresh VM with VirtualBox and attached the disks created for VMplayer with it and repeated the tests. Well, I got the same performances from the new VM and somehow I came to a conclusion that, both VirtualBox and VMPlayer provide better I/O for SCSI interfaces compared to plain SATA emulators, ironically, the disks were created over SATA drives!

This difference you may not experience with VMs those are not hosting resource hungry applications like Oracle E-Business Suite. So, if you are attempting what I had described above and notice the differences, please update me with comments section.