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Nimble OS 2.0 Part 3: Nimble Connection Manager for VMware


Nimble OS 2.0 provides many powerful new capabilities. The first blog in this series described how Automatic Connections are enabled with Nimble OS 2.0 for Windows and VMware hosts Nimble OS 2.0 Part 1: Manual vs Automatic Networking and the second how to configure Nimble Connection Manager (NCM) for Windows Nimble OS 2.0 Part 2: Nimble Connection Manager for Windows

This time we’ll look at how to install and leverage Nimble Connection Manager (NCM) in vSphere environments. This software includes two “vSphere Installation Bundles” or VIBs, and these will manage all of your ESX iSCSI connections and MPIO settings:

  • Nimble Connection Service (NCS) – Automatically calculates and maintains the optimal number of iSCSI sessions between the ESX host and Nimble Storage;
  • Nimble Path Selection Plugin (PSP): Nimble PSP for VMware Pluggable Storage Architecture – Automatically directs I/O to the most favourable route.


NCM is supported with Nimble OS 2.0 and later and ESX 5.0 and later. Note: to install NCM you require vSphere Enterprise or Enterprise Plus versions which support the “Storage APIs for Array Integration Multipathing”. For future ESX and Nimble OS version support you can always check the Support Matrix available on InfoSight.

There are 3 possible ways to install the NCM:

  1. Online NCM bundle (download and install with single esxcli command);
  2. Offline NCM bundle (download bundle and manually install with esxcli commands);
  3. Offline NCM bundle via vSphere Update Manager.

I’m going to use option 2 as typically this is the process that I use with customers. First download the NCM software from InfoSight (https://infosight.nimblestorage.com) which provides step by step instructions on all installation methods and configuration. 

If this is a new install you should first add an iSCSI adapter to your ESX host, create your vSwitch(es), add your vmkernel ports for iSCSI, and then bind them to the iSCSI adapter in ESX. If you need assistance with these steps see the VMware Integration Guide for more info. My environment has two hosts, each with two standard vSwitches, and a single subnet used for iSCSI:

ESX environment - 1.pngvSwitches - 2.png

From a storage point of view I have a single Nimble Group with 2 arrays and the disks from each array are pooled together in a single Storage Pool (called Default). In this configuration I’m pooling all of my capacity and performance together.

Architecture - 3.png

So with the environment described, let’s look at the installation steps for NCM: 

  1. Copy the NCM package to the ESX hosts, typically I use WinSCP and place the zip file in /tmp
  2. Place the ESX host(s) in to maintenance mode
  3. Connect to the ESX hosts as root and run the following command:

    esxcli software vib install -d /tmp/ncm-2-0-7-0-nimble-ncm-2.0.7-500005.zip --no-sig-check

  4. Next verify the install with the following command:

    esxcli software vib list | grep nimble

  5. The final step is to take the ESX host back out of maintenance mode, and you’re done.


Note – the ESX host(s) does need to be in maintenance mode for the install so schedule it around a time when this is possible. Also if you upgrade NCM in the future to match a later Nimble OS firmware release this will require an ESX host reboot.

If you haven’t already, configure ESX iSCSI adapter with the Discovery Address for the group, which in my case is the same as my Virtual Target IP (VTIP). Note that on the array Active Configuration illustration below I’ve also configured my array iSCSI Host Connection Method for “Automatic” and “Enable rebalancing” – these settings along with NCM means that all my IO requests and data access paths will be optimised regardless of which array in the group the data resides on.

    Network config - 4.pngiSCSI Discovery - 5.png

And now you’re ready to provision some storage. You can do this either through the vSphere plugin or through the array GUI.

Once you’ve provisioned the storage you can see from ESX the paths to a given datastore and the Nimble PSP managing the Active I/O (MPIO) across them.

MPIO - 6.png

And from the Nimble array GUI you can see the initiators connected (one per ESX node) and the iSCSI connections (four from each host to the Nimble Array Group):

  iSCSI Connections - 7.png

So the final word, if you only have the Standard edition of vSphere which doesn’t support a 3rd party PSP, you can still configure MPIO in the traditional way and this is described in the VMware Integration Guide referenced earlier (also see this NimbleConnect thread: Importance of Path Change Settings in VMware)

I hope you found this blog useful. The next in this series looks at how to upgrade from Nimble OS 1.4.x to 2.0.x. If you have any questions please post them below or contact your local Nimble SE.


About the Author



The majority of our Nimble customers run vSphere Essentials or Essentials Plus.  This plugin is essentially useless to us.  How about a happy medium where you just use the RoundRobin policy and automate the selection of it and the zero IOPs load balancing methodology so we don't have to manually run scripts anymore.

- Chris


Hi Chris

Unfortunately a 3rd party PSP is only supported with Enterprise/Enterprise Plus versions.

I did check with one of our dev team to see if we could set via the Nimble vCenter Plugin when a volume/datastore is created as an alternative method, unfortunately we can't set the IOPS/Bytes though as this isn't available via the API. For now we have to use the script method.



I was looking to set this up and based on this article and Nick Dyer's I wasnt terribly confident about the order of things.

It sorta sounded like if i changed the network config on the array it might cause an issue with clients that didnt have NCM installed.

currently I just have VMware using my nimble array and i've setup update manager to push the extension, but as far as updating the hosts and doing the automated network config, didnt know what the order should be.



Hi Justin

There is a doc on InfoSight which covers this. Login to InfoSight, go to Downloads, Nimble OS, Select (GA) software version, then review the "1.4 to 2.0 Migration (README FIRST)" document.

This outlines the order, which is: 1. Check you're on 1.4.7 2. Prepare network configuration. 3. Configure network bisect or even/odd if needed. 4. Allocate Virtual Target IPs. 5. Install NCM. 6. Update Nimble OS to 2.0.7. 7. Enable Automatic Connection Method. 8. Configure NCM. 9. Enable Rebalanacing.

Hope this helps, post back if you need more or give Nimble Support a call/email and they'll be more than happy to help.




Hi Chris, thanks for your comments.

to add to what Jason said above, NCM for VMware becomes very important when implementing a scale-out Nimble solution, as volumes may be distributed and load balanced across two or more systems. Other vendors which implement scale-out typically deploy a solution where one array does iSCSI redirects to tell the host which array holds the data it requires at that time. This introduces latency & overhead which is not acceptable in our solution. Therefore NCM includes a bitmap which is constantly updated in real time and understands exactly which NIC/path/array/eth port to use in order to fetch the data required in the lowest latency & time possible.

If a customer is using Essentials licensing, then the chances of needing to have a scale-out group (and therefore NCM for VMware) is minimal in my opinion.


That makes sense.  I guess I just misunderstood the reasoning for NCM.  I thought the purpose was to automate & simplify the load balancing steps that we were doing manually.  I didn't realize NCM was implemented to support the new scale-out functionality.  We are not as concerned with scale-out to that degree, as most of our customers are not very likely to need it.  It would be nice if the Nimble plugin could automate the load balancing & best practice tuning settings that we are having to script or run manually, much like Netapp does with their vCenter plugin. It doesn't have to be the equivalent of NCM. Just something to make our lives a little easier and make sure our Nimble/VMware configs are consistent and will perform at their best.




Hi Chris,

Yes I absolutely understand where you're coming from. NCM will do all the connection management, MPIO, best practice tuning and other nice stuff too, but as we've had to build it via a VMware PSP to get the functionality desired including the scale out management we're restricted to VMware's licensing model of Enterprise or Enterprise Plus.

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