6.0

8 Click Next.
9 In the Ready to Complete New Virtual Machine page, review your selections.
10 Click Finish to complete your virtual machine.
Manage Paths for a Mapped Raw LUN
You can manage paths for mapped raw LUNs.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system or an ESXi host.
Procedure
1 Log in as administrator or as the owner of the virtual machine to which the mapped disk belongs.
2 Select the virtual machine from the Inventory panel.
3 On the Summary tab, click Edit Settings.
4 On the Hardware tab, select Hard Disk, then click Manage Paths.
5 Use the Manage Paths dialog box to enable or disable your paths, set multipathing policy, and specify
the preferred path.
For information on managing paths, see “Understanding Multipathing and Failover,” on page 333.
Understanding Multipathing and Failover
To maintain a constant connection between a host and its storage, ESXi supports multipathing. Multipathing
is a technique that lets you use more than one physical path that transfers data between the host and an
external storage device.
In case of a failure of any element in the SAN network, such as an adapter, switch, or cable, ESXi can switch
to another physical path, which does not use the failed component. This process of path switching to avoid
failed components is known as path failover.
In addition to path failover, multipathing provides load balancing. Load balancing is the process of
distributing I/O loads across multiple physical paths. Load balancing reduces or removes potential
bottlenecks.
NOTE Virtual machine I/O might be delayed for up to sixty seconds while path failover takes place. These
delays allow the SAN to stabilize its configuration after topology changes. In general, the I/O delays might
be longer on active-passive arrays and shorter on active-active arrays.
Path Scanning and Claiming
When you start your ESXi host or rescan your storage adapter, the host discovers all physical paths to
storage devices available to the host. Based on a set of claim rules, the host determines which multipathing
plug-in (MPP) should claim the paths to a particular device and become responsible for managing the
multipathing support for the device.
By default, the host performs a periodic path evaluation every 5 minutes causing any unclaimed paths to be
claimed by the appropriate MPP.
The claim rules are numbered. For each physical path, the host runs through the claim rules starting with
the lowest number first. The attributes of the physical path are compared to the path specification in the
claim rule. If there is a match, the host assigns the MPP specified in the claim rule to manage the physical
path. This continues until all physical paths are claimed by corresponding MPPs, either third-party
multipathing plug-ins or the native multipathing plug-in (NMP).
Chapter 24 Managing Storage in the vSphere Client
VMware, Inc. 333