IP Multipathing Setup In Nexenta

A feature added in NexentaStor 3.1.4 is the ability to configure IP Multipathing (IPMP) groups via the management console (NMV) rather than having to drop to the shell and configure it manually.

IPMP has two purposes: fault-tolerance and outbound traffic load spreading. While there’s a lot of overlap between Link Aggregation and IPMP, there are some key differences. For more on that, you can read Nicolas Droux’s great write up:
https://blogs.oracle.com/droux/entry/link_aggregation_vs_ip_multipathing.

By default, NMV created IPMP groups with link based failure detection rather than probe based. Link based detection is lighter than probe based as it relies on the lower level detection link state rather than a test IP address.

To configure IPMP:

  1. Log into the management console and navigate to Settings -> Network.
    Screen Shot 2013-04-08 at 7.27.04 PM
  2. Click Create.
  3. Select ‘IPMP‘ from the Interface Type drop down menu.
    1. Be careful not to choose the NIC being used for management or other in-use traffic. It’s presented here because it’s technically allowable to add an in-use NIC to an IPMP group.
  4. Select the Network Interface Cards to be a part of the IPMP group.
  5. Select an IP Address assignment method.
    1. If you chose Static, enter the IP address and Network Mask info
  6. Select a Standby NIC (this is for incoming traffic, outbound will use both links)
    Screen Shot 2013-04-08 at 7.27.51 PM
  7. Click Create
    Screen Shot 2013-04-08 at 7.28.14 PM

That’s it! A pretty simple way to add fault-tolerance to your NexentaStor whether you’re using file or block connectivity. For setups like iSCSI, if you have 4 NICs, you can have 2 IPMP groups on 2 separate subnets to enable LUN multipathing and gain valuable resiliency and bandwidth.

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