Hello and welcome to disk types. In this lesson, we're going to take a look at the different disk types that are available in Microsoft Azure. We'll take a look at ultra disks, SSD disks, and HDD disks. We'll also take a look at bursting as well.

Let's start with ultra disks. Ultra disks in Azure are designed for high IOPS usage. These disks provide low latency storage for Azure virtual machines. When you leverage ultra disks with virtual machines, you can dynamically change their performance without needing to restart the VM itself. You would generally use ultra disks for workloads that are data intensive. Such workloads include things like high-end databases and other transaction-heavy workloads. I should point out, however, that you can only use ultra disks as data disks. They cannot be used as OS disks.

Ultra disks can be as small as four gig and as large as 64 terabytes. They support up to 300 IOPS per gigabyte, up to a maximum of 160,000 IOPS per disk. The size of the ultra disk will determine its IOPS and throughput capacity.

At the time of this course publication, ultra disks are only supported in a handful of regions and on only a handful of virtual machine series. Other limitations of ultra disks include the fact that they can only be created as empty disks and that they do not support snapshots, VM images, availability sets, or disk encryptions. There are also several other limitations as well.

For more information on ultra disks, visit the URL that you see on your screen.

Let's take a look at premium SSD disks now. Premium SSDs in Azure are designed to provide high performance and low latency storage for virtual machines. These disks are the recommended choice for IO-intensive workloads. Organizations typically use premium SSD disks to support mission-critical applications. However, I should mention that premium SSDs can only be used with virtual machines that support premium storage. This means not all VMs can use premium SSD disks.

The size of a premium SSD disk will determine some of its capabilities. For example, if you look at the table on your screen, you can see that there are several different sizes to choose from. If you look at provisioned IOPS per disk in this table, you can see that P1 disks offer roughly 10% of what P15 disks offer.

When a premium SSD disk is provisioned, its storage capacity, IOPS, and throughput are all guaranteed. So, for example, if you provision a P2 disk, Azure will provision eight gig of capacity, 120 IOPS, and 25 megabytes per second in throughput for that disk. This means you're going to be charged for this capacity, whether you use it or not.

Let's take a look at bursting now. Bursting is an automated process that works on a credit system. It's supported by premium SSD disks that are smaller than P30. What bursting does is allow a disk to burst its IOPS to 3500 and its bandwidth to 170 megabits per second.

When you use bursting, you automatically accumulate credits in what is called a burst bucket. These credits are accumulated during times when your disk traffic is below your provisioned performance target. When your traffic goes beyond the defined target, you consume these burst credits.

Bursting is useful for OS disk boots and for applications with uneven traffic. And support for bursting is automatically enabled on all new deployments of disks that qualify for bursting.

To read more about disk bursting, visit the URL that you see on your screen.

Now, let's take a look at standard disks starting with standard SSDs. Standard SSD disks are a cost-effective storage option for virtual machines that do not require the high IOPS that are offered by ultra disks and premium SSDs. These disks, which are backed by solid-state drives, offer affordable performance and better availability than standard HDDs.

Organizations will often use standard SSD disks for development and testing, and for light-duty production workloads like web servers and application servers that have low IOPS requirements.

Standard SSD disks are available on all virtual machines in Azure. The table on your screen highlights the many different sizes that are available, the IOPS per disk for each size, as well as the throughput per disk for each size. Generally speaking, standard SSDs will outperform their HDD counterparts due to their lower latency.

The last disk we're going to talk about here is the standard HDD disk. Standard HDDs in Azure are backed by magnetic drives. They are low-cost disks that you can use for VMs that host workloads with no real latency or IOPS requirements.

The table on your screen highlights the standard HDD disk sizes, along with their associated IOPS and throughput.

Because standard HDD disks are the lowest-performing type of disks available for Azure VMs, they are generally used in limited cases, such as development and testing, and for non-critical workloads. Standard HDDs are available for all Azure VMs in all Azure regions.

To learn more about standard HDDs, visit the URL that you see on your screen.