vDCA550-Objective 1.3-1-Perform command line configuration of Multipathing options

There are three defaults Path select Policies (PSP) available in VMWARE.

Most Recently used (MRU)

The host picks a path at the time of boot. The path will remain active until its fails. When the default path is fail it will automatically switch to the second (alternative) path. But when the original path becomes available again. It will not revert or go back to the first path. It is the default policy for ACTIVE/PASSIVE Storage device.

Fixed

This is the default policy for VMWARE. If the preferred path is not set than host picks a path on boot time. You can change the preferred path manually. The path will remain active until its fails. When the default path is fail it will automatically switch to the second (alternative) path. But when the original path becomes available again. It will automatically revert or go back to the first path. It is the default policy for ACTIVE/ACTIVE Storage device.

Round Robin

With this PSP the storage request is rotated and load balance through all “active paths” in the ACTIVE/PASSIVE Storage device. But the storage request is rotated and load balance through “all available” paths in ACTIVE/ACTIVE storage devices.

You can find the default Multipathing plug-in from CLI and GUI as well.

From CLI:

#esxcli storage nmp psp list

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From GUI:

From Webclient ->Home-> Storage-> Select your device (Datastore) -> Manage-> Settings -> Connectivity and Multipathing -> Select the Host -> Click “Edit Multipathing” Button.

Here is the list of default Multipathing pluggings.

vDCA550-Obj-1-3-cmdlinemultipathing-02

Multipathing Plug-in can be configured and install from the ESXCLI command in the ESXi host. The default SATP (Storage Array Type Plugin) for iSCSI or FC devices is VMW_SATP_DEFAULT_AA. if there is no SATP policy assign to a device. The default PSP is VMW_PSP_FIXED.

To display the installed Multipathing plug-in in an ESXi host.

#esxcli storage core plugin list

vDCA550-Obj-1-3-cmdlinemultipathing-03

Similarly you can find the default SATP plug-in In an ESXI host

#esxcli storage nmp satp list

vDCA550-Obj-1-3-cmdlinemultipathing-04

Check the Multipathing of a Specific Device.

You can find the default SATP and PSP setting for a device using both command client and GUI as well.

From CLI.

#esxcli storage nmp device list 

vDCA550-Obj-1-3-cmdlinemultipathing-05

From GUI:

You can see your configured Path Selection Policy (PSP) and Storage Array Type Policy (SATP) in the Multipathing details section of storage.

vDCA550-Obj-1-3-cmdlinemultipathing-06

Change the Default Multipathing of a device.

There are two options available when come to change the default Multipathing policy. Multipathing policy can be configured on per device basis. But if you have lots of devices in the environment then you can change the default PSP of a SATP. It will automatically change the PSP to all devices which associated to that Storage array type policy (SATP) .let’s do both configurations one by one.

1-Change the PSP of a device

From CLI:

First Check the default PSP of a Device.

#esxcli storage nmp device list 

vDCA550-Obj-1-3-cmdlinemultipathing-05

Example: As you can see above we have “Fixed” PSP Policy is configured which comes default with VMWARE. Let’s change it to “Round Robin”

#esxcli storage nmp device set –d t10.F405E46494C45425837546174494D2958787E4D284248366 –P VMW_PSP_RR

vDCA550-Obj-1-3-cmdlinemultipathing-07

You can verify your configured PSP settings

#esxcli storage nmp device list (Go to you device and check Path Selection Policy (PSP))

vDCA550-Obj-1-3-cmdlinemultipathing-08

From GUI.

From Webclient ->Home-> Storage-> Select your device (Datastore) -> Manage-> Settings -> Connectivity and Multipathing -> Select the Host -> Click “Edit Multipathing” Button.

vDCA550-Obj-1-3-cmdlinemultipathing-09

 Select your Multipathing from Drop Down and Click “OK”

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Verify your configured settings

vDCA550-Obj-1-3-cmdlinemultipathing-11

2-Change the  default PSP of a SATP.

Example: I am going to change the PSP of the following SATP (VMW_SATP_DEFAULT_AA) to Round Robin. Which comes with default VWM_PSP_FIXED PSP Policy

First check the default SATP plug-in In an ESXI host

#esxcli storage nmp satp list

vDCA550-Obj-1-3-cmdlinemultipathing-04

Now change it to Round Robin

#esxcli storage nmp satp set –s VMW_SATP_DEFAULT_AA –P VMW_PSP_RR

vDCA550-Obj-1-3-cmdlinemultipathing-12

Verify the configured setting.

#esxcli storage nmp satp list

vDCA550-Obj-1-3-cmdlinemultipathing-13

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