Datasheet

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CHAPTER 1 INTRODUCING VMWARE VSPHERE 5
cluster of ESXi hosts, Storage DRS helps balance storage capacity and storage performance across a
cluster of datastores using mechanisms that echo those used by vSphere DRS.
I described vSphere DRS’s feature called intelligent placement, which automates the
placement of new VMs based on resource usage within an ESXi cluster. In the same fashion,
Storage DRS has an intelligent placement function that automates the placement of VM vir-
tual disks based on storage utilization. Storage DRS does this through the use of datastore
clusters. When you create a new VM, you simply point it to a datastore cluster, and Storage
DRS automatically places the VM’s virtual disks on an appropriate datastore within that
datastore cluster.
Likewise, just as vSphere DRS uses vMotion to balance resource utilization dynamically,
Storage DRS uses Storage vMotion to rebalance storage utilization. Because Storage vMotion
operations are typically much more resource intensive than vMotion operations, vSphere pro-
vides extensive controls over the thresholds, timing, and other guidelines that will trigger a
Storage DRS automatic migration via Storage vMotion.
STORAGE I/O CONTROL AND NETWORK I/O CONTROL
VMware vSphere has always had extensive controls for modifying or controlling the allocation
of CPU and memory resources to VMs. What vSphere didn’t have prior to the release of vSphere
4.1 was a way to apply these same sort of extensive controls to storage I/O and network I/O.
Storage I/O Control and Network I/O Control address that shortcoming.
Storage I/O Control allows vSphere administrators to assign relative priority to storage I/O
as well as assign storage I/O limits to VMs. These settings are enforced cluster-wide; when an
ESXi host detects storage congestion through an increase of latency beyond a user-con gured
threshold, it will apply the settings con gured for that VM. The result is that VMware adminis-
trators can ensure that the VMs that need priority access to storage resources get the resources
they need. In vSphere 4.1, Storage I/O Control applied only to VMFS storage; vSphere 5 extends
that functionality to NFS datastores.
The same goes for Network I/O Control, but for network traffi c on the physical NICs. As the
widespread adoption of 10 Gigabit Ethernet continues, Network I/O Control provides VMware
administrators a way to more reliably ensure that network bandwidth is properly allocated to
VMs based on priority and limits.
PROFILE-DRIVEN STORAGE
With profi le-driven storage, a new feature found in vSphere 5, vSphere administrators are able
to use storage capabilities and VM storage profi les to ensure that VMs are residing on storage
that is able to provide the necessary levels of capacity, performance, availability, and redun-
dancy. Pro le-driven storage is built on two key components:
u Storage capabilities, leveraging vSphere’s storage awareness APIs
u VM storage pro les
Storage capabilities are either provided by the storage array itself (if the array is capable of
using vSphere’s storage awareness APIs) and/or defi ned by a vSphere administrator. These stor-
age capabilities represent various attributes of the storage solution.
VM storage profi les defi ne the storage requirements for a VM and its virtual disks. You create
VM storage profi les by selecting the storage capabilities that must be present in order for the VM
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