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NetApp ONTAP disk management using simulator

NetApp ONTAP disk management using the simulator is a great opportunity to learn about the NetApp offering. In particular for those who run a homelab it is a nice kit to add and understand more about the configuration. When installing the NetApp ONTAP simulator for the first time it deploys with a standard configuration. It consists in 28 emulated disks over 2 shelves. In reality the NetApp ONTAP simulator allows up to 4 disk shelves with disks up to 9 GB each. But what expanding or changing the default configuration?

This is what this article is about: deleting the built-in disk configuration and create new ones from scratch. It goes without saying a backup of the data sitting on the ONTAP simulator should be protected prior to follow any further step. Literally the existing disks (emulated drives in the ONTAP simulator) will be wiped and recreated again.

Now the simulator allows to create different types of NetApp ONTAP disk for SAS and FC connected storage:

Storage typeNetApp Disk typeDisk classDisk type

This article explores the option to delete the existing disk configuration, remove the emulated disks and create new ones based on specific templates. In particular 3 tiers for Capacity, Performance and Ultra-Performance. These come handy in homelab setup when simulating different tiers of storage differentiating between standard and critical applications. More on this later on a dedicated article.

The process might look quite lengthy. In reality is very quick. Once acknowledged the commands the procedure is straight forward. This means the NetApp ONTAP simulator could be configured up to half terabyte of storage. That is 9 GB x 56 disk slots over 4 disk shelves. A whopping 504 GB. Not bad for homelab! In reality the NetApp ONTAP simulator is limited to 220 GB by default. In order to extend this to 500 GB there is another hack. But this will be covered in a second part with detailed step by step. 220 GB for a homelab are enough to cover many scenario.


Increase NetApp ONTAP disk storage

One of the first things to change the NetApp ONTAP disk configuration is to connect to the ONTAP appliance using an SSH connection. This is enabled by default. Otherwise this can be configured in the default OnCommand System Manager as part of the protocols allowed for the users.

In this case the Putty utility is used for the SSH connection to the ONTAP appliance. Once connected and authenticated a simple Disk show will reveal the main information about the disk details including the Node owners in the cluster.

domalab.com NetApp ONTAP disk

Before deleting the disks it is necessary to remove the owner with the storage disk removeowner command followed by disk name.

domalab.com NetApp ONTAP disk

At this point a disk show again will display the updated information.

domalab.com NetApp ONTAP disk

Next step is to enable the diag user. This can be done by simply entering in the security context and execute:

security login unlock -username diag

At which point a new password needs to be provided and confirmed (the terminal wont display the characters typing!)

domalab.com NetApp ONTAP disk

Next is enable the Advanced mode with the set -privilege advanced and confirm with a yes. This step might be required from NetApp ONTAP 9.4 and later. It is also worth noting the * symbol on the shell with next commands in this context.

At this point it is a matter of accessing the local shell to make the big changes to the emulated disk configuration. Before doing this it is necessary to carry on with the “diag” user and the chosen password. Next step is to run the systemshell local command and enter the diag password.

domalab.com NetApp ONTAP disk

Caution at this point is required. The System Shell gives low level access to the ONTAP system. It is important at this point to create a variable. Something like setenv PATH “${PATH}:/usr/sbin” followed by an echo $PATH to confirm is returning the locations were to search/run the binaries.

Next is to change directory and move to the one listing all the emulated disks. The command is cd /sim/dev/,disks

A simple ls command will list all the emulated disks.

domalab.com NetApp ONTAP disk

The name of the emulated disks include the shelf, disk number, type (NetApp virtual disk), size, type and speed.

Next step is to start removing the virtual drives by running a sudo rm v0.* for the very fist shelf.

Now the same for the remaining disks on the other shelves.

Last but not least remove also the reservations file with a simple sudo rm ,reservations.

Next step is to move to the dev folder to run the binary which creates the virtual disk with the -h command.

cd /sim/dev

vsim_makedisks -h

This will now show all the NetApp ONTAP disk types that can be generated. The very first number on the left column represents the ID for such disks types. For Reference a simple output for all disk types can be downloaded here.

domalab.com NetApp ONTAP disk

At this point it is possible to start creating the disks based on the desired ID. To create the Ultra-Performance tier made of SSD disks the command would be similar to sudo vsim_makedisks -n 10 -t 35 -a 0

Essentially create 10 disks SSD type (ID 35) on first shelf which is called “0”. 4 disk shelves from 0 to 3.

Likewise it is possible to proceed creating the other disk types for the other storage tiers. For example Capacity with another 10 Disks of 9 GB each based on ID 36 on shelf 2.

And why not, another 10 disks still 9 GB each of type 37 on shelf 3 this time.

A simple ls ,disks/ will list all the newly created emulated disks inside the ONTAP appliance.

At this point it is just a matter of rebooting the node and confirm the command.

The NetApp ONTAP node will take a few seconds to restart and first thing is to pay attention to the screen and press Ctrl-C to enter the Boot menu.

Next action is to press option “5” to enter the Maintenance Mode.

domalab.com NetApp ONTAP disk

From the Maintenance Mode executing a disk show -n will show the disks created along with the current owner.

As expected these disks are not assigned to any Node owner yet. A quick test can be done by manually assigning these disk to the current node. This can be easily accomplished by running the disk assign command followed by the disk names.

domalab.com NetApp ONTAP disk

A disk show command again reflects the latest changes with disks ownership.

domalab.com NetApp ONTAP disk

It is time to halt or reboot the node again with halt command followed by any key to reboot.

domalab.com NetApp ONTAP disk

After the reboot cycles through a Ctrl-C will bring the same menu again. In this case it is a matter to follow the “standard” first time configuration.

domalab.com NetApp ONTAP disk

Now when browsing the Disks Inventory from the OnCommand System Manager it is possible to see the newly created disks types and ready to use.

domalab.com NetApp ONTAP disk


About the author

Michele Domanico

Passionate about Virtualization, Storage, Data Availability and Software Defined Data Center technologies. The aim of Domalab.com is sharing with the Community the knowledge and experience gained with customers, industry leaders and like minded peers. Always open to constructive feedback and new challenges.


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    • Hi RM,
      you should be able to create a login using any email address. Maybe try with a “work one” and avoid anonymous ones like gmail, hotmail etc.. Let me know how it goes.
      Kind regards,

  • Hi Michele,
    I’m trying to add 1 shelf with FACL disk (type 36) and 3 shelf SSD (type 35) but only one shelf per type is visible. There’s no way to make visible shelf 3 and 4? What I wrong?

    Many thanks for your help.

    • Hi Alessandro,

      thanks for your comment. If I get your question correctly please note the 4 shelves are called 0,1,2,3. So when assigning the first disks you could start from shelf “0”. Hope this helps.

      Kind Regards,

  • Did you ever write another piece about how to expand the simulator beyond the 220 GB limit? I cant seem to find anything on that. Thanks… Mike

    • Hi Mike,
      I was happy with the 220GB for my homelab and did not need 500+ for additional testing 🙂 I found this video that goes with similar steps. Basically you need to detach the vmdk from the NetApp Sim, change/edit the vmdk to thin provisioning and re-attach again. This video covers the details https://www.youtube.com/watch?v=JWJuXS7WmAk. Hope this helps. Thanks, Michele

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