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2019/11/18 13:52 1 Comment

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Create New Datastore with NetApp OnCommand System Manager

My company experienced some performance problems so I created a new storage design in which was decided there should be a maximum of 4 VMs per datastore. That means a lot more creating and adjusting datastores, but limiting the number of VMs per datastore increases the number of SCSI commands to the datastore per VM which increases the reaction time of storage related events. This article shows you how to create a new datastore which is done by doing the following steps:

  1. Checking for availability of space
  2. Resizing the volume where the datastore will reside
  3. Creating a LUN and mapping this to the ESX Cluster
  4. Creating the datastore
  5. Setting MPIO optimal settings

Check Space Availability

Available storage in NetApp filers is contained in aggregates. So in NetApp onCommand System Manager select the aggregate section and check for available space:

Resize the Volume

After you've checked for enough available space at the aggregate the volume resides in, you can select the volume in the OnCommand Storage Manager and click the resize button:
This will start the “Volume Resize Wizard”, and you can click 'Next' on the welcome page. You're now presented with a graphical overview in which you can set the new size:
After clicking 'Next' you are presented with the option to delete snapshot copies to free up space. Since we only use snapshots on replicated volumes and these snapshot are cleaned up automatically you can click next here. You can now review your changes and click 'Next' to resize the volume. When the resizing is done you can click 'Finish' to close the wizard.

Create a LUN

After resizing the volume you can create the LUN. To do so go into the LUNs section and click the 'Create' button:
You're now presented with the “Create Lun Wizard” where you can click 'Next' on the welcome page. In the next Window you have to provide the name (see below for the naming convention) and description (LUN for ESX Cluster <city>-<clustername>). You also have to provide the Type (VMware), the size and whether you want the LUN Thin provisioned (yes):
After clickin 'Next' you can select the volume whoch you've resized:
Now click 'Next' to select the initiator group. Select the initiator group named after the ESX Cluster where the datastore will reside and provide the unique LUN ID which is also part of the name:
Now review your settings in the next screen and click 'Next' to create the LUN.

Create the Datastore

To create the datastore we switch to vCenter where we select one host that should have access to the created LUN. Go to the Configuration tab, select storage and click 'Rescan All'. Select only the “Scan for New Storage Devices” and click ok. When the scan is ready click the 'Add Storage' button to start the “Add Storage Wizard”. In the first window, select the storage type as Disk/LUN and click 'Next':
Select the storage device you've added which can be recognized by the size (capacity) and the LUN ID:
After clicking 'Next' you can review the disk layout and click 'Next' again. Then enter a name, which should be exactly the same as the LUN name, and click 'Next':
Now you must decide on the block size. The block size controls the maximum size of your VMs disks. Select the one that is appropriate for you and click 'Next': createdatastorenoc09.jpg
Click finish to create the datastore. After creating the datastore vCenter will request the other hosts in the cluster to scan for VMFS datastores.

Set MPIO Optimal Settings

Note that setting the MPIO settings is not required if you have a alua enabled san.

To set the correct MPIO settings you'll first have to check if the host has dead paths, so check for this in the configuration of the host by going to the storage adapters, and select the path view after selecting the fiber channel adapters. Dead paths look like this:
If there are dead paths you should try to rescan the storage with the 'Rescan All' button in the topright corner. If that is not successful the only solution is to reboot the host.
Now you have to obtain the Identifier of the storage lun. You can do so in the devices view where you added the datastore:
To set the optimal MPIO settings logon to the Service Console from the host (any SSH client will do) and issue this command:

/opt/ontap/santools/config_mpath --primary --loadbalance --policy fixed --name naa.60a98000572d4371434a6c2d31526146

If you leave out the –name section the command will check the optimal MPIO settings for all LUNs. That is not a problem, it will just take some time to complete.


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createdatastorenoc.txt · Last modified: 2019/11/18 12:22 (external edit)