Setting Multipathing Policies for LUNs

The following multipathing policies are currently supported:

Fixed — The ESX Server host always uses the preferred path to the disk when that path is available. If it cannot access the disk through the preferred path, then it tries the alternate paths. Fixed is the default policy for active/active storage devices.

Most Recently Used — The ESX Server host uses the most recent path to the disk until this path becomes unavailable. That is, the ESX Server host does not automatically revert back to the preferred path. Most Recently Used is the default policy for active/passive storage devices and is required for those devices.

The ESX Server host automatically sets the multipathing policy according to the make and model of the array it detects. If the detected array is not supported, it is treated as active/active. For a list of supported arrays, see the SAN Compatibility Guide.

Note: Manually changing Most recently used to Fixed is not recommended.

To Set the Multipathing Polices 

• Log into the VMware VI Client, and select a server from the inventory panel.
• Click the Configuration tab, and click Storage (SCSI, SAN, and NFS) under hardware.
• From the list of configured datastores, select the datastore whose paths you want to view or configure, and click Properties.

The Volume Properties dialog box for this datastore opens.

• The Extent Device panel includes information on the status of each path to the storage device. The following path information appears:

          Active- The path is working and is the current path being used for transferring data.
          Disabled – The path has been disabled and no data can be transferred.
          Standby – The path is working but is not currently being used for transferring data.
          Dead-  The software cannot connect to the disk through this path.

• Click Manage Paths to open the Manage Paths wizard.

If you are using path policy Fixed, you can see which path is the preferred path. The preferred path is marked with an asterisk (*) in the fourth column.

The Manage Paths wizard shows the list of different paths to the disk, with the multipathing policy for the disk and the connection status for each path. It also shows the preferred path to the disk.  

 

• Under the policy Click change

 

Select one of the following options:

• Fixed
• Most RecentlyUsed

Click OK, and click Close to save your settings and return to the Configuration page.

How to add a storage to ESX

Adding Local SCSI Storage
As soon as you load SCSI storage adapter drivers, ESX Server detects available SCSI storage devices. Before creating a new datastore on a SCSI device, you might need to perform a rescan.
When you create a datastore on a SCSI storage device, the Add Storage wizard guides you through the configuration steps.
To create a datastore on a local SCSI disk

• Log into the VMware VI Client and select the server from the inventory panel.
• Click the Configuration tab, and click Storage (SCSI, SAN, and NFS) under hardware.
• Click the Add Storage link.
• Select the Disk/LUN storage type, and click Next.

•  Select the SCSI device you want to use for your datastore, and click Next.
•  Look over the current disk layout, and click Next. 
•  Enter a datastore name. (The label name must be unique within the current Virtual Infrastructure instance) 
•  Click Next.

• If needed, adjust the file system and capacity values.

           By default, the entire free space available on the storage device is offered to you.

• Click Next.
• Review the datastore configuration information, and click Finish.

This process creates a datastore on the local SCSI disk on your ESX Server host.

Adding Fibre Channel Storage
Before creating a new datastore on a Fibre Channel device, rescan a Fibre Channel adapter to discover any newly added LUNs. 

When you create a datastore on a Fibre Channel storage device, the Add Storage wizard guides you through the configuration.
To create a datastore on a Fibre Channel device

• Log into the VMware VI Client, and select a server from the inventory panel.
• Click the Configuration tab, and click Storage (SCSI, SAN, and NFS) under hardware.
• Click the Add Storage link..
• Select the Disk/LUN storage type, and click Next.

• Select the Fibre Channel device you want to use for your datastore, and click Next.
• Look over the current disk layout, and click Next. 
• Enter a datastore name.
• The datastore name appears in the VI Client and must be unique within the current Virtual Infrastructure instance. 
• Click Next.

• If needed, adjust the file system values and capacity you use for the datastore.
  By default, the entire free space available on the storage device is offered to you.
• Click Next.
• Review the datastore information, and click Finish.
  This process creates the datastore on a Fibre Channel disk for the ESX Server host. 
• Perform a rescan

Creating an NFS-Based Datastore

When you create a datastore on an NFS volume, the Add Storage wizard guides you through the configuration steps.

To mount an NFS volume

• Log into the VMware VI Client, and select a server from the inventory panel.
• Click the Configuration tab, and click Storage (SCSI, SAN, and NFS) under hardware.
• Click the Add Storage link.
• Select Network File System as the storage type, and click Next.

• Enter the server name, the mount point folder, and the datastore name.
• Click Next.
• Review the configuration options and click Finish.

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