vSphere Storage - ESXi 5.0 - Documentation - VMware
vSphere Storage - ESXi 5.0 - Documentation - VMware
vSphere Storage - ESXi 5.0 - Documentation - VMware
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<strong>vSphere</strong> <strong>Storage</strong><br />
Use Disk Shares to Prioritize Virtual Machines<br />
If multiple virtual machines access the same VMFS datastore (and therefore the same LUN), use disk shares<br />
to prioritize the disk accesses from the virtual machines. Disk shares distinguish high-priority from lowpriority<br />
virtual machines.<br />
Procedure<br />
1 Start a <strong>vSphere</strong> Client and connect to the vCenter Server.<br />
2 Select the virtual machine in the inventory panel and click Edit virtual machine settings from the menu.<br />
3 Click the Resources tab and click Disk.<br />
4 Double-click the Shares column for the disk to modify and select the required value from the drop-down<br />
menu.<br />
Shares is a value that represents the relative metric for controlling disk bandwidth to all virtual machines.<br />
The values Low, Normal, High, and Custom are compared to the sum of all shares of all virtual machines<br />
on the host. Share allocation symbolic values can be used to configure their conversion into numeric values.<br />
5 Click OK to save your selection.<br />
NOTE Disk shares are relevant only within a given <strong>ESXi</strong> host. The shares assigned to virtual machines on one<br />
host have no effect on virtual machines on other hosts.<br />
Choosing Virtual Machine Locations<br />
When you’re working on optimizing performance for your virtual machines, storage location is an important<br />
factor. A trade-off always exists between expensive storage that offers high performance and high availability<br />
and storage with lower cost and lower performance.<br />
<strong>Storage</strong> can be divided into different tiers depending on a number of factors:<br />
n High Tier. Offers high performance and high availability. Might offer built-in snapshots to facilitate<br />
backups and point-in-time (PiT) restorations. Supports replication, full SP redundancy, and SAS drives.<br />
Uses high-cost spindles.<br />
n Mid Tier. Offers mid-range performance, lower availability, some SP redundancy, and SCSI or SAS drives.<br />
May offer snapshots. Uses medium-cost spindles.<br />
n Lower Tier. Offers low performance, little internal storage redundancy. Uses low end SCSI drives or SATA<br />
(serial low-cost spindles).<br />
Not all applications need to be on the highest-performance, most-available storage—at least not throughout<br />
their entire life cycle.<br />
NOTE If you need some of the functionality of the high tier, such as snapshots, but do not want to pay for it,<br />
you might be able to achieve some of the high-performance characteristics in software. For example, you can<br />
create snapshots in software.<br />
When you decide where to place a virtual machine, ask yourself these questions:<br />
n How critical is the virtual machine?<br />
n What are its performance and availability requirements?<br />
n What are its PiT restoration requirements?<br />
n What are its backup requirements?<br />
n What are its replication requirements?<br />
26 <strong>VMware</strong>, Inc.