EMC VNX/MCx Storage Pool Expansion – NavisecCLI or Unisphere

Storage Pool Expansion on EMC VNX/MCx arrays is a simple, straightforward task that can be done to increase capacity, performance or both.

It is an online operation (NDU) but I always try to initiate it when load on an array is non-peak. The process is just like a Fast VP data relocation.

Of course there’s more than one way to do this task, the GUI way and the fun way with CLI!

Method 1 . Naviseccli.

This utilizes the storagepool command with the –expand option.

In my case I will be expanding Storage Pool ID # 4 with 5 x disks in 2_1_10 :14 into an existing Performance tier. ( I can omit the –rtype option to choose a RAID type). If you want to skip the background verify task you can use the –initialverify no or use yes and limit the rate.


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And we’re off. Progress of the rebuild can be monitored with;

To watch it progress in actual time, you can use the following Powershell script snippet to call and filter the naviseccli command;

In action;

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…….and done. (that’s 100.00% ! )

Method 2.  – Unisphere

Select your pool, click expand. Either accept the disks chosen for you or click on Manual and select them yourself

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Leave the default options (unless you want to increase/decrease the background verify priority which scans the new disk looking for any latent soft media errors) and click ok.

Job done. This will trigger a “Rebalance” of the pool tier. Progress can be checked by going into the Pool properties, where the State will have changed from “Ready” to Rebalancing with a “% complete” counter as the operation progresses.

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You can also get information from the Tiering Tab, where you can see the time remaining, data to be moved (intra-tier).












Happy days.






























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4 thoughts on “EMC VNX/MCx Storage Pool Expansion – NavisecCLI or Unisphere

  1. I like to manually select drives when expanding pools, default template allways wants to grab drives that i have “designated” as hot spares. No designated HS on VNX2 but you know what i mean 🙂

  2. because of a bug in flare you will not be able to extend a pool by more than 16 disks with manual disk selection. EMC support confirmed this to me. For any reason the KB article is not available to customers so you will not find any hint for this bug.

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