Adding option to disable bootscrub in XenServer

When you start XenServer, there will be a bootscrub process that happens during boot. This may take some time if you've a large amount of RAM, or are running  nested XenServer instances. 

In the Xen model, domains are responsible for clearing any sensitive data they have out of memory before shutdown. This is a safety feature to prevent accidentally leaking sensitive VM data into other VMs if Xen crashes and reboots.

If this is not a concern for you, then you can easily turn bootscrub off by adding


to the boot options (

To modify boot command line options 

For XenServer 6.5 - change the file /boot/extlinux.conf

For XenServer 7.0 - change the file /boot/grub/grub.cfg