6.0.1

Table Of Contents
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Become familiar with the various monitor points in your storage network, at all visibility points,
including host's performance charts, FC switch statistics, and storage performance statistics.
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Be cautious when changing IDs of the LUNs that have VMFS datastores being used by your ESXi host.
If you change the ID, the datastore becomes inactive and its virtual machines fail. You can resignature
the datastore to make it active again. See “Managing Duplicate VMFS Datastores,” on page 162.
If there are no running virtual machines on the VMFS datastore, after you change the ID of the LUN,
you must use rescan to reset the ID on your host. For information on using rescan, see “Storage Refresh
and Rescan Operations,” on page 124.
Disable Automatic Host Registration
Certain storage arrays require that ESXi hosts register with the arrays. ESXi performs automatic host
registration by sending the host's name and IP address to the array. If you prefer to perform manual
registration using storage management software, disable the ESXi auto-registration feature.
Procedure
1 Browse to the host in the vSphere Web Client navigator.
2 Click the Manage tab, and click .
3 Under System, click Advanced System .
4 Under Advanced System Seings, select the Disk.EnableNaviReg parameter and click the Edit icon.
5 Change the value to 0.
This disables the automatic host registration enabled by default.
Optimizing Fibre Channel SAN Storage Performance
Several factors contribute to optimizing a typical SAN environment.
If the environment is properly congured, the SAN fabric components (particularly the SAN switches) are
only minor contributors because of their low latencies relative to servers and storage arrays. Make sure that
the paths through the switch fabric are not saturated, that is, that the switch fabric is running at the highest
throughput.
Storage Array Performance
Storage array performance is one of the major factors contributing to the performance of the entire SAN
environment.
If there are issues with storage array performance, be sure to consult your storage array vendors
documentation for any relevant information.
Follow these general guidelines to improve the array performance in the vSphere environment:
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When assigning LUNs, remember that each LUN is accessed by a number of hosts, and that a number
of virtual machines can run on each host. One LUN used by a host can service I/O from many dierent
applications running on dierent operating systems. Because of this diverse workload, the RAID group
containing the ESXi LUNs should not include LUNs used by other servers that are not running ESXi.
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Make sure read/write caching is enabled.
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SAN storage arrays require continual redesign and tuning to ensure that I/O is load balanced across all
storage array paths. To meet this requirement, distribute the paths to the LUNs among all the SPs to
provide optimal load balancing. Close monitoring indicates when it is necessary to rebalance the LUN
distribution.
vSphere Storage
60 VMware, Inc.