Oracle RAC: "The parent virtual disk has been modified since the child was created. The content ID of the parent virtual disk does not match the corresponding parent content ID in the child"

This is a fairly generic share disk error. The reason I am getting this is when setting Oracle RAC on 2 VMs, I did not include  ""diskLib.dataCacheMaxSize = "0" " to my VMX files on both VMs. So, upon starting up node2, it throws that error.

"The parent virtual disk has been modified since the child was created. The content ID of the parent virtual disk does not match the corresponding parent content ID in the child"

Resolution - add  "diskLib.dataCacheMaxSize = "0" to the VMX file on all cluster nodes.

Oracle RAC: " The process cannot access the file because another process has locked a portion of the file."

Adding a shared disk to the ASM disk group. Upon starting node2, it throws an error of "The process cannot access the file because another process has locked a portion of the file.". The reason for this is, VMX needs to enable disk sharing. This is only needed for adding a shared SCSI disk on VMware Workstation. Oracle Virtualbox has its own easier way to share disks.

Insert the following line to the VMX file. 

"disk.locking = "FALSE"

As a side note for adding a share disk on Oracle Virtualbox, all needed are the following steps.

--Open VirtualBox Manager Window

File | Virtual Media Manager

Select the new disk

Properties

Change Type from Normal to Shareable.

Click Apply.

Oracle RAC: INS-40912 Virtual host name xxxxx is assigned to another system on the network

While installing the grid software, I encountered the issue of " INS-40912 Virtual host name xxxxx is assigned to another system on the network". It took me a while to realize, that I actually have the IP set on one of my eth interfaces as well as in the /etc/hosts file of the VIP IP section, it has been assigned to the VIP. So. the error did not lie about it. I had 2 IPs co-existed on the eth2 and also the /etc/hosts's VIP section. If you run into this issue, just make sure the IPs on the VIP section are not used or assigned to anything within the RAC or on the network. Normal ping on the IPs and name should help narrow down the issue. The chance of the later is low as during the setup, the installation will locate unused IPs for the VIP.