- Native Multipathing
- Storage Array Type Plug-in (SATP)
- Path Selection Plugin (PSP)
- Third-Party Plug-ins
- Multipathing Plugins (MPPs)
- Anatomy of PSA Components
- I/O Flow Through PSA and NMP
- Listing Multipath Details
- Claim Rules
- MP Claim Rules
- Plug-in Registration
- SATP Claim Rules
- Modifying PSA Plug-in Configurations Using the UI
- Modifying PSA Plug-ins Using the CLI
Modifying PSA Plug-in Configurations Using the UI
You can modify PSA plug-ins’ configuration using the CLI and, to a limited extent, the UI. Because the UI provides far fewer options for modification, let me address that first to get it out of the way!
Which PSA Configurations Can Be Modified Using the UI?
You can change the PSP for a given device. However, this is done on a LUN level rather than the array.
Are you wondering why you would want to do that?
Think of the following scenario:
You have Microsoft Clustering Service (MSCS) cluster nodes in Virtual Machines (VMs) in your environment. The cluster’s shared storage is Physical Mode Raw Device Mappings (RDMs), which are also referred to as (Passthrough RDMs). Your storage vendor recommends using Round-Robin Path Selection Policy (VMW_PSP_RR). However, VMware does not support using that policy with the MSCS clusters in shared RDMs.
The best approach is to follow your storage vendor’s recommendations for most of the LUNs, but follow the procedure listed here to change just the RDM LUNs’ PSP to their default PSPs.
Procedure to Change PSP via UI
- Use the vSphere client to navigate to the MSCS node VM and right-click the VM in the inventory pane. Select Edit Settings (see Figure 5.35).
Figure 5.35. Editing VM’s settings via the UI
The resulting dialog is shown in Figure 5.36.
Figure 5.36. Virtual Machine Properties dialog
- Locate the RDM listed in the Hardware tab. You can identify this by the summary column showing Mapped Raw LUN. On the top right-hand side you can locate the Logical Device Name, which is prefixed with vml in the field labeled Physical LUN and Datastore Mapping File.
- Double-click the text in that field. Right-click the selected text and click Copy (see Figure 5.37).
Figure 5.37. Copying RDM’s VML ID (Logical Device Name) via the UI
- I use the copied text to follow Steps 4 and 5 of doing the same task via the CLI in the next section. However, for this section, click the Manage Paths button in the dialog shown in Figure 5.37.
The resulting Manage Paths dialog is shown in Figure 5.38.
Figure 5.38. Modifying PSP selection via the UI
- Click the pull-down menu next to the Path Selection field and change it from Round Robin (VMware) to the default PSP for your array. Click the Change button. To locate which PSP is the default, check VMware HCL. If the PSP listed there is Round Robin, follow the examples listed in the previous section, “SATP Claim Rules,” to identify which PSP to select.
- Click Close.