Dell PowerVault MD3000 - Manual (Page 36)

Dell MD Storage Array vCenter Plug-in | 36
Decision-Making Schemes
When the storage characterization for a virtual machine is not available, you can use either the predictive
scheme or the adaptive scheme to decide on the virtual disk size and number of virtual disks to use.
Using the Predictive Scheme to Make virtual disk Decisions
1
Create several virtual disks with different storage characteristics.
2
Build a VMFS Datastore on each virtual disk. Label each Datastore according to its characteristics.
3
Allocate virtual disks to contain the data for virtual machine applications in the VMFS datastores built
on virtual disks with the appropriate RAID level for the applications' requirements.
4
Use disk shares to distinguish high-priority virtual machines from low-priority virtual machines.
NOTE: Disk shares are relevant only within a given host. The shares assigned to virtual machines on one
host have no effect on virtual machines on other hosts.
5
Run the applications to determine whether virtual machine performance is acceptable.
Using the Adaptive Scheme to Make Virtual Disk Decisions
1
Create a large virtual disk, such as RAID 1+0 or RAID 5, with write caching enabled.
2
Build a VMFS datastore on that virtual disk.
3
Place four or five virtual disks on the VMFS datastore.
4
Run the applications to determine whether disk performance is acceptable.

If performance is acceptable, you can place additional virtual disks on the VMFS datastore.

If performance is not acceptable, create a new, larger virtual disk, and repeat the process. You can use a
different RAID level. Use migration so that you do not lose virtual machines when you re-create the virtual
disk.