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Multipathing Configuration

for Software iSCSI Using

Port Binding

T e c h n i c a l W h i T e P a P e R

Using Port Binding

• Multipathing for Software iSCSI Table of contents
• Configuring vmknic-Based iSCSI Multipathing
• a) Configuring the Network
  • 1. Using GUI
    • 2. Using CLI
• b) Enabling the iSCSI Software Adapter
  • 1. Using GUI
    • 2. Using CLI
• c) Activating vmknic-Based Multipathing for Software iSCSI
  • 1. Configuring Port Binding on vSphere 5.0 Using GUI
    • 2. Configuring Port Binding on vSphere 5.0 Using CLI
  • 3. Configuring Port Binding on vSphere 4.x Using CLI
• iSCSI Re-login
• Verifying Multipath Configuration
  • 1. Verifying the iSCSI LUN Configuration
    • 2. Verifying vmknic-Based Multipath Failover
  • 3. Verifying Load Balancing Using the Round-Robin Policy
• Conclusion
• About the Author

Using Port Binding

3. Click Add Networking.

4. Select VMkerneland click Next.

5. Select Create a vSphere standard switch to create a new vSwitch.

6. Select all the adapters you want to configure for iSCSI traffic and. click Next

7. Provide a Network Label for the VMkernel port group and click Next.

8. Specify the IP address settings and click. Next

9. Review the details on the Summaryscreen and click Finish.

Next, to create an additional VMkernel port group to configure port binding, complete the following steps:

1. Click the Propertiestab of the vSwitch you created for iSCSI.

2. Create additional VMkernel ports for all network adapters that you connected by selectingtab the Add under the Ports tab in the vSwitch Properties dialog box.

3. Select VMkerneland click Next.

4. Provide a Network Label for the VMkernel port group and click Next.

5. Specify the IP address settings and click. Next

6. Review the details on the Summaryscreen and click Finish.

You can also create VMkernel port groups on different vSwitches. However, if your VMkernel network adapters are on the same subnet, they must be configured on the same vSwitch.

Using Port Binding

All network adapters that you added to the vSwitch will appear as active for each VMkernel port on the vSwitch. Ensure that you override this configuration so that each VMkernel port maps to only one active adapter.

1. In the Portstab of the vSwitch Properties dialog box, select a VMkernel port and click Edit.

2. Click the NIC Teaming tab and check Override switch failover order.

3. Keep only one adapter under Active Adaptersand use Move Down to move other adapters under Unused Adapters.

Using Port Binding

6. Map each VMkernel port to use only one active adapter and to move the second network adapter to unused adapter list: esxcfg-vswitch -N vmnic4 -p iSCSI-PG1 iscsivSwitch.

7. Map each VMkernel port to use only one active adapter and to move the second network adapter to unused adapter list: esxcfg-vswitch -N vmnic5 -p iSCSI-PG2 iscsivSwitch.

8. Assign an IP address to the first port esxcfg-vmknic group: -a -i 192.168.100.1 -n 255.255.255.0 iSCSI-PG.

9. Assign an IP address to the second port esxcfg-vmknic group: -a -i 192.168.100.2 -n 255.255.255.0 iSCSI-PG.

b) Enabling the iSCSI Software Adapter

1. Using GUI

To access iSCSI targets, you must enable the software iSCSI initiator on the VMware ESXi server.

Procedure

1. Connect to the ESXi server using vSphere Client.

2. Click Configuration > Storage Adapters.

3. Enable the iSCSI software adapter.

a. For ESXi server releases prior to vSphere 5.0, iSCSI Software Adapter is listed under the Storage Adapters tab. i. Select iSCSI Software Adapter and click Properties. ii. Under the Generaltab, click Configure. iii. Check Enabledto enable the initiator. iv. To change the default iSCSI initiator name, enter iSCSI initiator name in the iSCSI Name box.

b. For vSphere 5.0, you must add iSCSI Software Adapter to the Storage Adapterscategory. i. Click Configuration > Storage Adapters. ii. Click Addand check Add Software iSCSI Adapter.

iii. To change the default iSCSI initiator name, enter iSCSI initiator name in the iSCSI Name box under the Configure tab in the iSCSI Software Adapter Properties window.

Using Port Binding

4. Enter the iSCSI target address in Static/Dynamic Discovery.

Dynamic Discovery – Specify the addresses for Send Targets discovery. The iSCSI initiator sends a Send Targets request to each of the specified addresses, and the discovered targets are added to the static discovery list.

Static Discovery – A list of IP addresses and iSCSI names of targets to connect to. This list can be filled in based on dynamic Send Targets requests or entered individually. This is a list of targets with which ESX attempts to establish sessions.

5. Click Closeto finish iSCSI initiator configuration.

Using Port Binding

f) Repeat steps d) and e) until you bind all the required VMkernel adapters to the iSCSI adapter.

Using Port Binding

NOTE: The port group policy status might report as noncompliant for the VMkernel network adapter for the following reasons:

- The VMkernel network adapter is not connected to an active physical network adapter or it is connected to _more than one physical network adapter.

• The VMkernel network adapter is connected to standby physical network adapters.
• The active physical network adapter got changed._

g) Close the iSCSI Initiator Properties window.

h) Select the software iSCSI adapter and run to verify that multiple paths are available for iSCSI LUNs.Rescan

Using Port Binding

Verifying Multipath Configuration

1. Verifying the iSCSI LUN Configuration

After you complete the port binding configuration and perform the iSCSI adapter rescan, verify that iSCSI LUNs are detected and displayed with the available paths. For example, if you have bound two VMkernel network adapters to the iSCSI adapter, you will see two paths to each LUN connected to the iSCSI targets. To confirm, run the esxcfg-mpath command from CLI or click the Paths tab for LUNs on the GUI.

Sample output Before port binding, there is one path available to each target (T0, T1).

After port binding two VMkernel network adapters to the iSCSI adapter, there are two paths available to each target (T0, T1).

2. Verifying vmknic-Based Multipath Failover

To identify the VMkernel network adapter currently used by the iSCSI adapter to transmit I/O, run the esxtop command. In the following example, I/O is transmitted through vmk1 (vmnic5).

To verify vmknic-based multipath failover, disable any one of the network adapters connected to the VMkernel port group used for iSCSI. Verify that the path status is updated correctly and that the paths connected to the failed network adapter card are marked as dead.

Using Port Binding

In the esxtop output, the failed network adapter is marked as fallback and the I/O is transferred using the other VMkernel port group.

3. Verifying Load Balancing Using the Round-Robin Policy

After configuring multipath failover for the software iSCSI, you can balance I/O traffic between the paths using the round-robin path policy.

NOTE: Verify that the iSCSI array supports the round-robin path policy by contacting the array vendor.

Change the path selection policy (PSP) for iSCSI LUNs either from the command line, by selecting the Manage Paths option, or by running the following command:

- esxcli storage nmp satp set -s SATP_NAME -P VMW_PSP_RR

To find the SATP name used to claim the iSCSI LUNs, run the following command:

- esxcli storage nmp device list -d naa.600601602af129007d698975a6f2e

Run the esxtop command to verify that I/O is distributed across the available paths for the iSCSI LUN.

To increase aggregated IO performance one can change RoundRobin IO Operation Limit to a lower value from default 1000.