6.5.1

Table Of Contents
Set Storage I/O Control Resource Shares and Limits
Allocate storage I/O resources to virtual machines based on importance by assigning a relative amount of
shares to the virtual machine.
Unless virtual machine workloads are very similar, shares do not necessarily dictate allocation in terms of
I/O operations or megabytes per second. Higher shares allow a virtual machine to keep more concurrent I/O
operations pending at the storage device or datastore compared to a virtual machine with lower shares. Two
virtual machines might experience dierent throughput based on their workloads.
Prerequisites
See vSphere Storage for information on creating VM storage policies and dening common rules for VM
storage policies.
Procedure
1 Find the virtual machine in the vSphere Web Client inventory.
a To nd a virtual machine, select a data center, folder, cluster, resource pool, or host.
b Click the VMs tab.
2 Right-click the virtual machine and click Edit .
3 Click the Virtual Hardware tab and select a virtual hard disk from the list. Expand Hard disk.
4 Select a VM storage policy from the drop-down menu.
If you select a storage policy, do not manually congure Shares and Limit - IOPS.
5
Under Shares, click the drop-down menu and select the relative amount of shares to allocate to the
virtual machine (Low, Normal, or High).
You can select Custom to enter a user-dened shares value.
6
Under Limit - IOPS, click the drop-down menu and enter the upper limit of storage resources to
allocate to the virtual machine.
IOPS are the number of I/O operations per second. By default, IOPS are unlimited. You select Low (500),
Normal (1000), or High (2000), or you can select Custom to enter a user-dened number of shares.
7 Click OK.
Enable Storage I/O Control
When you enable Storage I/O Control, ESXi monitors datastore latency and throles the I/O load if the
datastore average latency exceeds the threshold.
Procedure
1 Browse to the datastore in the vSphere Web Client navigator.
2 Click the  tab.
3 Click  and click General.
4 Click Edit for Datastore Capabilities.
5 Select the Enable Storage I/O Control check box.
6 Click OK.
Under Datastore Capabilities, Storage I/O Control is enabled for the datastore.
vSphere Resource Management
52 VMware, Inc.