6.7

When you use SAN storage with ESXi, the following considerations apply:
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You cannot use SAN administration tools to access operating systems of virtual machines that reside
on the storage. With traditional tools, you can monitor only the VMware ESXi operating system. You
use the vSphere Client to monitor virtual machines.
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The HBA visible to the SAN administration tools is part of the ESXi system, not part of the virtual
machine.
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Typically, your ESXi system performs multipathing for you.
ESXi Hosts and Multiple Storage Arrays
An ESXi host can access storage devices presented from multiple storage arrays, including arrays from
different vendors.
When you use multiple arrays from different vendors, the following considerations apply:
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If your host uses the same SATP for multiple arrays, be careful when you change the default PSP for
that SATP. The change applies to all arrays. For information on SATPs and PSPs, see Chapter 18
Understanding Multipathing and Failover.
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Some storage arrays make recommendations on queue depth and other settings. Typically, these
settings are configured globally at the ESXi host level. Changing settings for one array impacts other
arrays that present LUNs to the host. For information on changing queue depth, see the VMware
knowledge base article at http://kb.vmware.com/kb/1267.
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Use single-initiator-single-target zoning when zoning ESXi hosts to Fibre Channel arrays. With this
type of configuration, fabric-related events that occur on one array do not impact other arrays. For
more information about zoning, see Using Zoning with Fibre Channel SANs.
Making LUN Decisions
You must plan how to set up storage for your ESXi systems before you format LUNs with VMFS
datastores.
When you make your LUN decision, the following considerations apply:
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Each LUN must have the correct RAID level and storage characteristic for the applications running in
virtual machines that use the LUN.
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Each LUN must contain only one VMFS datastore.
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If multiple virtual machines access the same VMFS, use disk shares to prioritize virtual machines.
You might want fewer, larger LUNs for the following reasons:
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More flexibility to create virtual machines without asking the storage administrator for more space.
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More flexibility for resizing virtual disks, doing snapshots, and so on.
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Fewer VMFS datastores to manage.
vSphere Storage
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