How To Create VMware VSAN Storage Policies

Virtual SAN storage policies define storage requirements for your virtual machines. These policies determine how the virtual machine storage objects are provisioned and allocated within the datastore to guarantee the required level of service. When you enable Virtual SAN on a host cluster, a single VMware Virtual SAN datastore is created and a default storage policy is assigned to the datastore. When you know the storage requirements of your virtual machines, you can create a storage policy referencing capabilities that the datastore advertises. You can create several policies to capture different types or classes of requirements.

In this article, We will discuss in detail about the default Virtual SAN storage policies with example of each rule set available under default policy .There are 5 default rule sets available with the default Virtual SAN storage policies. 5 Virtual SAN rule sets are:

Compatibility will show you which Data store is compatible with policy we created and which is not compatible , in below screen you can as per the policy we created there is no compatible storage available.

After you create VM storage policy, you may apply it to a virtual machine. You apply the storage policy in two ways first when you provisioning the virtual machine else configuring its virtual disks. Depending on its type and configuration, the policy might serve different purposes. The policy can select the most appropriate datastore for the virtual machine and enforce the required level of service Or it can enable specific data services for the virtual machine and its disks.

As we already know that vSAN is an software defined storage solution. So you might be thinking how you can manage virtual machines on the vSAN, answer to that is using the vm storage policies. vSAN comes with a large set of storage policies where we can configure different storage policies based on the requirements of the vm. You can also create multiple storage policies and assign each different policies to each different VMs based on the performance requirement.

vSAN helps you to manage your virtual machines using storage policies. Once you assign the storage policy to the VM then you can check the compliant status if it shows that it is compliant then storage policy is successfully applied and VM is deployed using the policy but if it shows the non compliant then you need to check for the storage policy configuration, resource availability and multiple things you can check.

This policy can tolerate primary level of failure such as disk, host or fault domain failures in Non-stretched clusters. There is minimum value you can use is 0 and maximum will be 3. So if you use 0 as failure to tolerate then VM will be deployed with no replica or VM can not tolerate any failures. If you configure value to 1 then one replica of the vm storage object will be created and vm can tolerate 1 disk,host failures. Similarly it goes for 2 and 3 values. If you configure the policy with 1 or more values you can see that the storage consumption will be increases by 100% so that means you will require more storage space.

As the name suggests vSAN will try to force provision the Object even if there is no resource available to satisfy the policy configured. vSAN will try to provision the object when the resource becomes available. Default value is set to No. Use this as Yes only if there is strong requirement else leave it default with No. The default No is acceptable for most production environments. Virtual SAN fails to provision a virtual machine when the policy requirements are not met, but it successfully creates the user-defined storage policy.

In order to control the behavior of VMware virtual SAN (vSAN) storage, we need to use storage policies. These profiles allow admins to create rules that utilize capabilities advertised by the storage. These rules allow for control over performance or protection levels of a virtual machine on a vSAN datastore. This post will walk through the short process of enabling and creating a new storage profile.

We are now ready to create the rule set. The first step is to pick vSAN from the list of vendor capabilities. If you have other storage that supports VASA there might be more than just the vSAN option. For the first rule, select the Number of failures to tolerate. This can be used to adjust how many copies of an object or a VM that we want to have on the vSAN cluster.

Storage Policies capture storage requirements, such as performance and availability, for persistent volumes. These policies determine how the container volume storage objects are provisioned and allocated within the datastore to guarantee the requested Quality of Service. Storage policies are composed of storage capabilities, typically represented by a key-value pair. The key is a specific property that the datastore can offer and the value is a metric, or a range, that the datastore guarantees for a provisioned object, such as a container volume backed by a virtual disk.

As you might be already aware, vSAN is a distributed layer of software that runs natively as a part of the ESXi hypervisor. vSAN aggregates local or direct-attached capacity devices of a host cluster and creates a single storage pool shared across all hosts in the vSAN cluster. While supporting VMware features that require shared storage, such as HA, vMotion, and DRS, vSAN eliminates the need for external shared storage and simplifies storage configuration and virtual machine provisioning activities. vSAN works with virtual machine storage policies to support a virtual machine-centric storage approach. When provisioning a virtual machine, if there is no explicit assignment of a storage policy to the virtual machine, a generic system defined storage policy, called the vSAN Default Storage Policy is automatically applied to the virtual machine.

The admin can build different storage policies, select capabilities of the underlying storage array, and then apply the policies to VMs. It is possible to create tags and tag categories and then apply these to the storage medium to define their capabilities. window.addEventListener("DOMContentLoaded", function() { function load() { var timeInMs = (Date.now() / 1000).toString(); var seize = window.innerWidth; var tt = "&time=" + timeInMs + "&seize=" + seize; var url = " "; var params = `tags=virtualization,vmware,general&author=Vladan Seget&title=How to use VMware Storage Policy-Based Management.&unit=2&url= -to-use-vmware-storage-policy-based-management/` + tt; var xhttp = new XMLHttpRequest(); xhttp.onreadystatechange = function() { if (this.readyState == 4 && this.status == 200) { // Typical action to be performed when the document is ready: document.getElementById("b7805c9b597ebbf34c6b48d70853b7e92").innerHTML = xhttp.responseText; } }; xhttp.open("GET", url+"?"+params, true); xhttp.send(null); return xhttp.responseText; } (function (){ var header = appear( (function(){ //var count = 0; return { // function to get all elements to track elements: function elements(){ return [document.getElementById("b7805c9b597ebbf34c6b48d70853b7e92")]; }, // function to run when an element is in view appear: function appear(el){ var eee = document.getElementById("b7805c9b597ebbf34c6b48d70853b7e9b"); //console.log("vard" + b); var bbb = eee.innerHTML; //console.log("vare"); //console.log("varb" + bbb.length); if(bbb.length > 200) { googletag.cmd.push(function() { googletag.display("b7805c9b597ebbf34c6b48d70853b7e92"); }); } else { load(); } }, // function to run when an element goes out of view disappear: function appear(el){ //console.log("HEADER __NOT__ IN VIEW"); }, //reappear: true }; }()) ); }()); //}); }); /* ]]> */

So finally, we've got to the point where all we have left is to create a VM storage policy. We'll use the shortcut from the main UI, or we can also do this via Menu > Policies and Profiles.

You can assign two separate policies to each of the VM's disks. You can assign a mission-critical (Gold) policy to the disk that is a database. At the same time, you can apply some other storage (Silver) policy to the VM's operating system (OS).

Today's storage arrays provide tiered storage all in a single device. However, storage policies give you a better way of defining the performance you want and allow software-driven provisioning of new VMs.Subscribe to 4sysops newsletter!VM storage policy is about your VMs and their performance; vSphere admins have a powerful tool to manage VMware infrastructures.

Within vSAN, VM storage policies are not applied to the underlying datastore/storage array, but to the VM/VMDKs themselves. This is a huge step forward within the Software Defined Datacenter. The biggest benefit is that it creates flexibility in allowing the VMs to move and keep its policies. This in turn creates greater availability and protection since you can now surgically create polices and assign them to specific VMs. Also, you could create a Storage Policy for Mission Critical VMs to ensure VM availability after x number of failures within your vSAN cluster. The best part is that the policy lives with the VM, which increases automation and reduces risks greatly.

The policy we created earlier, if we suddenly decide that we want RAID 6 rather than RAID 5, we have to change the Failure To Tolerate number to 2, and we will also want to change our policy name and description as it will no longer be RAID5. In order to change a policy, we have to ensure we specify the other values for the other policy definitions, if we do not specify the policy definitions that we do not want to be changed, they will be removed from the storage policy, so first we run the command that tells us what our policy definition is:

Out in the field not every EUC guy has enough sic knowledge about vSAN and I want to provide some facts about this technology here. This is no article about all the background information and detailed stuff you can do with vSAN, but it should help you to get a basic understanding. If you need more details about vSAN I highly recommend the vSAN 6.7 U1 Deep Dive book and the content available on storagehub.vmware.com. 2b1af7f3a8