Information Technology Reference
In-Depth Information
Working with VM-Level Storage Confi guration
Let's move from ESXi- and vSphere-level storage coni guration to the storage coni guration
details for individual VMs.
First, we'll review virtual disks and the types of virtual disks supported in vSphere. Next
we'll review the virtual SCSI controllers. Then we'll move into a discussion of VM storage poli-
cies and how to assign them to a VM, and we'll wrap up this discussion with a brief exploration
of using an in-guest iSCSI initiator to access storage resources.
Investigating Virtual Disks
Virtual disks (referred to as VMDKs because of the i lename extension used by vSphere) are
how VMs encapsulate their disk devices (if not using RDMs), and they warrant further discus-
sion. Figure 6.52 shows the properties of a VM. Hard disk 1 is a 30 GB thick-provisioned virtual
disk on a VMFS datastore. Hard disk 2, conversely, is an RDM.
Figure 6.52
h is VM has both
a virtual disk on
a VMFS datastore
and an RDM.
We discussed RDMs previously in the section “Working with Raw Device Mappings,” and
we'll discuss RDMs in a bit more detail in Chapter 7 as well. As you know already, RDMs are
used to present a storage device directly to a VM instead of encapsulating the disk into a i le on
a VMFS datastore.
