vSphere Storage - ESXi 5.1 - Documentation - VMware

vSphere Storage
Use the Predictive Scheme to Make LUN Decisions
When setting up storage for ESXi systems, before creating VMFS datastores, you must decide on the size and
number of LUNs to provision. You can experiment using the predictive scheme.
Procedure
1 Provision several LUNs with different storage characteristics.
2 Create a VMFS datastore on each LUN, labeling each datastore according to its characteristics.
3 Create virtual disks to contain the data for virtual machine applications in the VMFS datastores created
on LUNs with the appropriate RAID level for the applications' requirements.
4 Use disk shares to distinguish high-priority 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.
Use the Adaptive Scheme to Make LUN Decisions
When setting up storage for ESXi hosts, before creating VMFS datastores, you must decide on the number and
size of LUNS to provision. You can experiment using the adaptive scheme.
Procedure
1 Provision a large LUN (RAID 1+0 or RAID 5), with write caching enabled.
2 Create a VMFS on that LUN.
3 Create four or five virtual disks on the VMFS.
4 Run the applications to determine whether disk performance is acceptable.
If performance is acceptable, you can place additional virtual disks on the VMFS. If performance is not
acceptable, create a new, large LUN, possibly with a different RAID level, and repeat the process. Use migration
so that you do not lose virtual machines data when you recreate the LUN.
Choosing Virtual Machine Locations
When you’re working on optimizing performance for your virtual machines, storage location is an important
factor. A trade-off always exists between expensive storage that offers high performance and high availability
and storage with lower cost and lower performance.
Storage can be divided into different tiers depending on a number of factors:
n High Tier. Offers high performance and high availability. Might offer built-in snapshots to facilitate
backups and point-in-time (PiT) restorations. Supports replication, full SP redundancy, and SAS drives.
Uses high-cost spindles.
n Mid Tier. Offers mid-range performance, lower availability, some SP redundancy, and SCSI or SAS drives.
May offer snapshots. Uses medium-cost spindles.
n Lower Tier. Offers low performance, little internal storage redundancy. Uses low end SCSI drives or SATA
(serial low-cost spindles).
30 VMware, Inc.