What is your VM software?
How did you setup the disks and what storage solution are you using?
also note that Oracle only certified Oracle VM as certified platform and if you are using some other then double check the licensing policy for it.
For example, if I copy or remove the folder /u01/applmgr/UAT(size 100Gb) it is very slow in VM compared to normal server.
as suggested by Bashar, you need to check your disk configuration to get better IOPS.
Off topic - pl post in appropriate VM forum