Vcap-Dca Objective 1.3 – Configure And Manage Complex Multipathing And Psa Plugins

Front 1

Explain the Pluggable Storage Architecture (PSA) layout

Back 1

Storage Guide, pages 158-160

To manage storage multipathing, ESXi uses a collection of Storage APIs, also called the Pluggable Storage Architecture. This PSA is a modular framework that coordinates the simultaneous operation of multiple multipathing plugins (MPPs). The PSA allows 3rd party software developers to design their own load balancing techniques and failover mechanisms for a particular storage array, and insert their code directly into the ESXi storage I/O path.

Front 2

Multipathing/PSA Acronyms: PSA

Back 2

Storage Guide, pages 158-160

PSA - Pluggable Storage Architecture

Front 3

Multipathing/PSA Acronyms: NMP

Back 3

Storage Guide, pages 158-160

NMP - Native Multipathing Plugin.

Generic VMware multipathing module.

Front 4

Multipathing/PSA Acronyms: PSA

Back 4

Storage Guide, pages 158-160

PSP - Path Selection Plugin, also called Path Selection Policy. Handles path selection for a given device.

List PSP available:

esxcli storage nmp psp list

Front 5

Multipathing/PSA Acronyms: MPP

Back 5

Storage Guide, pages 158-160

MPP - Third party multipathing plugin.

Install third-party plugin:

esxcli software vib install -d

Front 6

Multipathing/PSA Acronyms: SATP

Back 6

Storage Guide, pages 158-160

SATP - Storage Array Type Plug-In, also called Storage Array Type Policy. Handles path failover for a given storage array.

List SATPs available:
esxcli storage nmp satp list

Set Default PSP for an SATP:

esxcli storage nmp satp set -s -P

List SATP Claim Rules:

esxcli storage nmp satp rule list

Front 7

Install and Configure PSA plug-ins: Install

Back 7

Storage Guide, page 164

esxcli software vib install

Front 8

Install and Configure PSA plug-ins: Check to see if plug-in is registered

Back 8

Command-Line Interface Concepts and Examples, page 46

esxcli storage core plugin registration list

Front 9

Install and Configure PSA plug-ins: Register a plug-in

Back 9

esxcli storage core plugin registration add -m -N SATP -P

Front 10

Install and Configure PSA plug-ins: Set a new default PSP for an SATP

Back 10

Command-Line Interface Concepts and Examples, page 87

esxcli storage nmp satp set -s -P

Front 11

Install and Configure PSA plug-ins: Claim a device under a different SATP

Back 11

Command-Line Interface Concepts and Examples, page 86

esxcli storage nmp satp rule add -s -d

Front 12

Understanding different multipathing policy functionalities: Fixed

Back 12

Command-Line Interface Concepts and Examples, page 46

Fixed

Always uses preferred path if available.

- VMW_PSP_FIXED
- Default for Active/Active Arrays.

The host will use a fixed path that is either set as the preferred path by the administrator, or is the first path discovered by the host during the boot process.

Preferred path can be set with vSphere Client or ESXi:

esxcli storage nmp psp fixed deviceconfig set -d -p

Front 13

Understanding different multipathing policy functionalities: Most Recently Used (MRU)

Back 13

Most Recently Used (MRU)

Uses most recently used path, no failback

- VMW_PSP_MRU
- Default for Active/Passive Arrays
- Default for ALUA devices

The host will use the path that is most recently used (MRU). When a path fails and another one is activated, the host will continue to use this new active path even when the original path comes back up.

Front 14

Understanding different multipathing policy functionalities: Round Robin (RR)

Back 14

Command-Line Interface Concepts and Examples, page 84

Round Robin (RR)

Rotates through available paths.

- VMW_PSP_RR
- Distributes I/O across configured paths.
- No default array types are listed for this PSP
- Make sure it is supported by array vendor.

Set path selection to specify when the path should change (bytes or iops):

esxcli storage nmp psp roundrobin deviceconfig set --type --device

Front 15

Understanding different multipathing policy functionalities: Set preferred path for fixed psp

Back 15

Command-Line Interface Concepts and Examples, page 46

esxcli storage nmp psp fixed deviceconfig set -d -p

Front 16

Understanding different multipathing policy functionalities: Set round robin path selection policy to specify when the path should change (byte or IOPS)

Back 16

Command-Line Interface Concepts and Examples, page 84

esxcli storage nmp psp roundrobin deviceconfig set --type --device

Front 17

Perform command line configuration of multipathing options: Change the PSP on a particular device

Back 17

Command-Line Interface Concepts and Examples, page 82

esxcli storage nmp device set -d -P

Front 18

Perform command line configuration of multipathing options: View device configurations based on assigned PSP

Back 18

esxcli storage nmp psp fixed deviceconfig get -d
(Command-Line Interface Concepts and Examples, page 46)

esxcli storage nmp psp generic deviceconfig get -d
(Command-Line Interface Concepts and Examples, page 83)

esxcli storage nmp psp roundrobin deviceconfig get -d
(Command-Line Interface Concepts and Examples, page 85)

Front 19

Perform command line configuration of multipathing options: Set a device to VMW_PSP_RR as default

Back 19

esxcli storage nmp psp roundrobin deviceconfig set -d -t default
(Command-Line Interface Concepts and Examples, page 85)

Front 20

Change a multipath policy: from GUI

Back 20

From Inventory -> Hosts and Clusters

1. Select a Host and click the Configuration tab.
2. In the left-hand pane, under Hardware, click on Storage.
3. Find the datastore you want to change and right-click on the datastore and click Properties.
4. On the properties window, click on Manage Paths.
5. From the Path Selection drop down, select the multipathing policy you want to change to.
6. Click Change.
7. Click Close.

Front 21

Change a multipath policy: from command-line

Back 21

Command Line Interface Solutions and Examples, P 46

esxcli storage nmp psp device set -d -P

Front 22

Change a multipath policy: set policy for an SATP

Back 22

esxcli storage nmp satp set --default-psp --satp

Front 23

Configure Software iSCSI port binding: from GUI

Back 23

Storage Guide, Pp 74 - 80

Ensure enough physical NICs for each vmkernel.

Configure each vmkernel to use only a single active NIC.

Configure each port group, likewise, to use only a single active NIC for that portgroup.

The idea is a one-to-one relationship of portgroup to vmnic/uplink and the same one-to-one relationship of vmknic/vmkernel portgroup to vmnic/uplink.

This will ensure that the storage traffic from each portgroup travels across one unique vmknic to a unique vmnic/uplink.

Lastly, make sure all vmknics are added to the network configuration on the iSCSI software initiator.

Front 24

Configure Software iSCSI port binding: from command-line

Back 24

Command Line Interface Solutions and Examples, P 77

esxcli iscsi networkportal add -A vmk1