IDE controller: why ICH6 over PIIX4?

[Antoine92]

Hi all,

I tried to setup an Ubuntu VM on a Windows host, starting with an ISO image, and the installation process stuck for hours after I chose the target partition.
What I noticed in MS ProcessExplorer : 

• CPU usage: stuck to 100% of CPU resources allocated to this VBox process (almost 100% system/kernel time)
• I/O: stays at ~50MB/s for hours ; according to VBox window icons (the ones that show drives activity), it's only optical drive I/O, the virtual hard drive is totally idle.

After 2 hours waiting, I killed the VM and tried with other Linux ISOs: same issue.
Then I tried with other IDE controller settings (default type was set to PIIX4), and finally the ICH6 type solved my problem: the Linux installation went quiclky without any CPU overuse.

I've used VBox for years on other hosts, never faced this issue before... so I call on the experts community: can anyone explain why/how to tweak these IDE settings? 
Thanks.

Antoine

[scottgus1]

We certainly could explain how to change the settings, just change the dropdown. That was easy.

Now as to why the settings need to be changed, that I don't know. The developers pick default hardware that the supported guest OS's will boot on.

If a guest OS's new version has advanced beyond what the developers know about and needs a different setup, then a change might be necessary. Maybe gather a reliably reproducible pattern with logs, then post it on the Bugtracker?

[ghr]

It is about the hardware, specifically HDD interface (or IO controller). PIIX comes from the ISA/IDE days and it is definitely not SATA aware. Modern OS 'es "assume" SATA so go for ICH6. So your selection depends on the age of the OS you want to install.

[brianw360]

Read your posts with great interest as I am trying to get CentOS 8.3 running on VB 6.1 on Win10. I've managed to install Ubuntu with no problem but my CentOS install doesn't seem to go past the preliminary Install menu.

I've made the change from PIIX4 to ICH6 with no success.