Preparing UNIX VMs with CentOS 7 or Older and RHEL 7 or Older for Conversion to VMware

For VMs that run either CentOS 7 (or a preceding version) or RHEL 7 (or a preceding version), before performing a backup that will be used for VM conversion, you must install the vmw_pvscsi driver on certain VMs.

These VMs include the following:

VMs running CentOS 7 or older
VMs running RHEL 7 or older

Procedure

To determine whether the required driver is built into the kernel itself, do the following:
1. Run the following command:
```
grep -i pvscsi /boot/config-$(uname -r)
```
2. Look for values of VMW_PVSCSI in the command output.
  
  If a driver's line reads y, then the driver is built into the kernel and is available by default during boot.
  
  If a driver's line reads m, then the driver needs to be part of the initial RAM disk.
To determine whether the driver is part of the initial RAM disk, run the following command:
```
lsinitrd | grep -i vmw_pvscsi
```
If the driver is missing from both the kernel and the initial RAM disk, rebuild the initial RAM disk to include the missing driver, as follows:
1. To create a backup of the current initial RAM disk image, run the following command:
```
 
cp /boot/<Current_Image_Name> /boot/[Current_Image_Name].backup
```
  Where [Current_Image_Name] is initramfs-$(uname -r).img
2. Edit the dracut.conf file as follows:
  
  Run the following command:
```
vi /etc/dracut.conf
```
  Uncomment the line that contains add_drivers, and then add the drivers to the line, with spaces separating each module, as follows:
```
add_drivers+="vmw_pvscsi"
```
3. To go to the boot folder, run the following command:
```
cd /boot
```
4. To recut the initial RAM disk image, run the following command:
```
dracut -f -v
```
5. To list the initial RAM disk image contents and to verify that the driver is added, run the following command:
```
lsinitrd | grep -i vmw_pvscsi
```