System information

Disable Automatic Host Registration
When you use EMC CLARiiON or Invista arrays for storage, the hosts must register with the arrays. ESX/ESXi
performs automatic host registration by sending the host's name and IP address to the array. If you prefer to
perform manual registration by using storage management software, turn off the ESX/ESXi auto-registration
feature.
Procedure
1 In the vSphere Client, select the host in the inventory panel.
2 Click the Configuration tab and select Advanced Settings under Software.
3 Select Disk in the left panel and scroll down to Disk.EnableNaviReg on the right.
4 Change the default value to 0.
5 Reboot the host for the changes to take effect.
This action disables the automatic host registration enabled by default.
Avoiding and Resolving SAN Problems
When using ESX/ESXi in conjunction with a SAN, you must follow specific guidelines to avoid SAN problems.
You should observe these tips for avoiding and resolving problems with your SAN configuration:
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Place only one VMFS datastore on each LUN. Multiple VMFS datastores on one LUN is not recommended.
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Do not change the path policy the system sets for you unless you understand the implications of making
such a change. In particular, working with an active-passive array and setting the path policy to Fixed can
lead to path thrashing.
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Document everything. Include information about zoning, access control, storage, switch, server and FC
HBA configuration, software and firmware versions, and storage cable plan.
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Plan for failure:
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Make several copies of your topology maps. For each element, consider what happens to your SAN
if the element fails.
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Cross off different links, switches, HBAs and other elements to ensure you did not miss a critical
failure point in your design.
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Ensure that the Fibre Channel HBAs are installed in the correct slots in the ESX/ESXi host, based on slot
and bus speed. Balance PCI bus load among the available busses in the server.
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Become familiar with the various monitor points in your storage network, at all visibility points, including
ESX/ESXi 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 ESX/ESXi
host. If you change the ID, virtual machines running on the VMFS datastore will fail.
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 “Rescan Storage
Adapters,” on page 56.
Fibre Channel SAN Configuration Guide
66 VMware, Inc.