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Why you should rename the default VSAN Datastore name

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Something that I have noticed early on when working with VSAN is that the VSAN datastore name is automatically selected for you and will always default to vsanDatastore. This is not a bad thing as it simplifies the setup of VSAN which is already dead simple. To enable VSAN, it is simply checking a box in the configuration of your vSphere Cluster just like you would when enabling vSphere DRS or HA.

From an operational standpoint, I think this can be a potential issue. What happens when you have a multiple VSAN Clusters under the same vSphere Datacenter object or even across different vSphere Datacenter objects? I recently came across this while re-building one of my lab environments, can you spot the problem in the screenshot below?

Here we have two VSAN Datastores within the same vSphere Datacenter. Datastore names under a single vSphere Datacenter must be unique. I am sure some of you may have already experienced this with local datastore names using the default "datastore1". vSphere will automatically append "(n)" to the name where n is the number of instances seen in the environment.

In this next example, we have two VSAN Datastores but they are split across two vSphere Datacenters. Since unique name is enforced at the Dataenter boundary, it is even worse now because you have the same name used across both VSAN Clusters.

Even though a user will most likely drill down into a specific environment when provisioning a Virtual Machine, I think it is critical to have a good naming scheme for your infrastructure. What happens when you have someone run an audit of all your VMs and all they showed for their datastore name was "vsanDatastore" and you had multiple VSAN Clusters? Would it not be more useful to have a bit more details in the datastore name to help map it back to some logical/physical container that is a bit more meaningful? I personally would think so and would help in times of troubleshooting where time is of the essence. 

Luckily this can easily be remediated since a VSAN Datastore operates just like any other datastore in which you can rename it. VSAN itself does not use the name to uniquely identify the datastore, it implements a unique UUID for each of the VSAN datastores. Simply renaming the VSAN Datastore to something more appropriate such as including the name of the vSphere Cluster will come a long when you need to correlate a Virtual Machine back to a particular compute/storage resource. 

I wonder if it would be a useful to have a feature in VSAN to automatically append the vSphere Cluster name to the default VSAN Datastore name? What do you think? 

vdq - A useful little VSAN utility

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While re-building a couple of my Nested ESXi VMs for VSAN using some newer builds, I came across a nifty little VSAN utility called vdq which I assume stands for either VMware Disk Query or VSAN Disk Query. I actually found this utility by accident while poking around in the ESXi Shell as I was looking for a quick way to inspect the disks and I know there are a couple other methods which are officially supported by VMware such as RVC or ESXCLI.

Disclaimer: This is not officially supported by VMware, please use at your own risk. 

vdq provides two useful commands, one that queries the disks on your ESXi host and show whether they are eligible or not for VSAN. The other is the disk mappings once VSAN has been configured and enabled on your ESXi host.

To query the disks on your ESXi host, you can run the following command: vdq -q

You will be presented with a lot of useful information such as the disk device name, VSAN node UUID, the state of the disk (whether or not it can be used by VSAN or if it is already in use), reason which includes more details, whether the disk is an SSD or HDD and also if the device is in a PDL (Permanent Device Loss) state.

You can also specify the -H option which makes the output a bit more readable as the default output is using Python. In this next screenshot, if we enable VSAN through the vSphere Web Client we now see that the VSANUUID property is now populated and the state of the disks have now changed.

The next command that is also handy once VSAN is enabled is to quickly get the VSAN disk group mapping by running the following command: vdq -i

With this command you can quickly find out the SSD that is front-ending the set of HDD for a given disk group. This command came in handy while re-building my ESXi hosts as I wanted to blow away the existing VSAN configuration. To do so, you would need to use ESXCLI and by leveraging vdq, I was able to quickly get the disk mappings and more importantly a command I could easily remember.

In general, I would still recommend using either ESXCLI or RVC which is already pretty simple to use but thought I share this little tip if you ever need to just quickly inspect an ESXi host for VSAN.

SPBM (Storage Policy Based Management) MOB in vSphere 5.5

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A handy little tool that was useful for me which might come in handy for others too while working on my VSAN VM Storage Policy recovery article is the SPBM (Storage Policy Based Management) MOB which works similar to the vSphere MOB and FDM MOB for those of you who have used this interface before. The MOB stands for Managed Object Browser and simply put is an interface that allows you to browse the objects and properties of your vSphere environment by just using a web browser. You can also interact with the MOB by executing the same set of vSphere API methods as you would if you were to write a script or application which is useful for quickly getting a sense of what a certain property might look like or the output of an API method without writing a single line of code.

In vSphere 5.5, there is now an SPBM API which is available as a separate API endpoint on the vCenter Server. This new API allows you to manage the full lifecycle of a VM Storage Policy formally known as VM Storage Profiles from a programmatic standpoint which is very important when working with VSAN as everything is policy driven. For more more details about the new SPBM API, please take a look here. As mentioned earlier, one great way to learn about the API is by exploring the MOB and luckily the SPBM API includes one!

To access the SPBM MOB in vSphere 5.5, you will need to point your browser to your vCenter Server as that is where the endpoint is exposed using the following URL format:

http://[VC-IP-OR-HOSTNAME]:8190/mob

To access the SPBM MOB in vSphere 6.0, you will need to point your browser to your vCenter Server as that is where the endpoint is exposed using the following URL format:

http://[VC-IP-OR-HOSTNAME]/pbm/mob

You will be prompted for your vCenter Server credentials before the MOB will allow you to login. Once you are logged in you will be brought to the main service content of the SPBM endpoint similar to the vCenter Server service content and you can then click on content link to explore the various sub-managers that are available.
Note: You will be able to get more details on each of these sub-managers by taking a look at the VM Storage Policy Programming Guide and VM Storage Policy API reference guide.
To quickly show you around, I will provide a couple of examples using the ProfileManager and I am sure you can probably guess what type of functionality it provides :). The first method that we will take a look at is the PbmQueryProfile which will return the list of available VM Storage Policies that have been defined. You will need to set the resourceType property to "STORAGE" and remove the profileCategory and then click on "Invoke Method".
If you are using VSAN and you do not have any VM Storage Policies defined, there will still be two default VM Storage Policies that is automatically created when VSAN is enabled. What you will see are the internal identifiers for each of the VM Storage Policy and as you can see from the output I have 5 VM Storage Policies.
You will notice that the output does not contain the human readable display name for each VM Storage Policy, to retrieve that information we will need to use the PbmRetrieveContent which accepts a list of VM Storage Profile ID's and in return provide the human readable name as well as other properties such as the initial creation date and last modified date. Using the pre-canned input form, you can specify one or more VM Storage Profile IDs from the previous step and then click on "Invoke Method".
In my example, I specified two of my VM Storage Policies and I can see they map to the names  "Aluminum" and "Copper" which is what I named them when I first created the policies.
From here on out, we will be using the VM Storage Policy ID as that is what is used to uniquely identify a VM Storage Policy and input for majority of the SPBM API methods. Now if we want to see what objects (VM Home directory or VMDKs) are associated with a particular VM Storage Policy we can use the PbmQueryAssociatedEntity method. You will need to provide the VM Storage Policy ID and remove the entityType and then click on the "Invoke Method".
As you can see from the output this a virtualMachine object type which tells us this VM Storage Policy is used for the VM Home. Lets go ahead and specify a VM Storage Policy that is used for a Virtual Machine's VMDK and see what that looks like.
We now see the object type is virtualDiskId and you can see the particular VMDK and the associated Virtual Machine by looking at the key which has the format of vm-mo-ref:vmdk-key. Now what if we wanted to perform the reverse look up, by providing only a Virtual Machine or VMDK as input? Well, we can easily do this lookup by using the PbmQueryAssociatedProfiles method. This API method requires you to specify three parameters: objectType, key and serverUuid (technically speaking the serverUuid can be left out).
From the above examples you will get an idea of what the expected input format is for either a Virtual Machine or VMDK query.
Here is an example of a Virtual Machine query:
Here is an example of a VMDK query:
Hopefully this quick introduction of the SPBM MOB will give you a good idea on how you can leverage this interface, especially if you plan on using the new SPBM API to automate and manage your VM Storage Policies.