Azure Disk Storage - Simply Explained

Today's topic is one that almost everyone has heard of, but most people don't fully understand, as your disk storage, it's the virtual hard drive for your cloud VMs and here's the thing, every single VM you create needs storage. Pick the wrong type and you're either paying way too much, or getting terrible performance. By the end of this episode, you'll know the four main disc types and exactly when to use each one. Grab your coffee and let's dive in. Why disk type matters? Speed, capacity and cost. So why does disk type even matter? Three factors determine performance. I/OPS, throughput and latency. I/OPS stands for input, output operations per second. Basically how many read or write operations the disk can handle at once. throughput is the data transfer speed measured in megabytes per second. Latency is the delay. How long that first byte takes to arrive after you ask for it? Think of it like vehicles. As the Dan handles daily errands just fine, a pickup truck holds heavier loads and a race car is built for pure speed. Different disk types follow the same pattern. Standard SSD is your sedan. Premium SSD is the work truck. Premium SSD V2 is a sports car you can tune yourself. And ultra-disc is a Formula 1 race car. Here's the trade-off, higher performance costs more money. The trick is matching the disk to what your workload actually needs, so you're not over-provisioning and wasting cash, nor under-provisioning and getting slow performance. So let's start with the two broad categories of disks you'll attach to a VM. OSDisk versus DataDisk, the two flavors. When you create a VM in Azure, it automatically creates an OSDisk. That disk holds the operating system, Windows or Linux, and it's where the VM boots from. The OSDisk maxes out at four terabytes, which is more than enough for the OS itself and maybe a few basic applications. But here's the thing, you can also add DataDisk. These are optional, and you attach them separately for things like applications, databases, or file storage. Each DataDisk can go up to 64 terabytes, and you can attach multiple disks to a single VM. Need more storage? Just add another disk. Now both OSDisk and DataDisk use the same four performance tiers. Standard SSD, premium SSD, premium SSD V2 and ultra-disk. The difference isn't about speed, it's about purpose. An OSDisk runs the operating system, a DataDisk runs your applications, but they both rely on the same underlying disk types. One more thing, as your disk storage is persistent, that means your data stays put even when the VM is stopped or restarted, nothing gets lost when you shut down for the night. Let's dive into the four tiers, starting with the most affordable. Standard SSD, the budget workhorse. Let's start with the entry-level option, Standard SSD. This is the lowest cost per gigabyte among the SSD tiers, and it gives you decent performance for basic workloads. We're talking about a maximum of around 6000 IOPS, and throughput up to 600 megabytes per second, depending on the disk size you choose. So when would you use it? Think development and test environments where you're spinning up VMs to experiment. Web servers that don't get heavy traffic, low traffic applications where a few seconds of delay isn't a big deal. Remember the vehicle analogy from earlier? Standard SSD is your reliable sedan. It gets you to the grocery store and back. It handles the daily commute just fine, but you wouldn't use it to hold a trailer full of lumber or race on a track. It's built for everyday tasks, not heavy lifting. And here's where you need to be honest with yourself. If you're running any kind of production database, SQL server, Oracle, MySQL, skip standard SSD. Same goes for anything sensitive to latency, like real-time applications, or anything that needs a ton of IO operations per second. Standard SSD just isn't built for that. For those scenarios, you need a step-up, premium SSD. Premium SSD, the reliable pro. Premium SSD handles production workloads without breaking a sweat. You get consistent low latency and much higher IO apps than standard SSD. This is where real performance starts showing up. Here's the simple breakdown. With premium SSD, performance is directly tied to the disk size. Pick a disk size and that determines how many IO apps you unlock. A P30 at one terabyte gives you 5,000 IOPS. A P60 at four terabytes delivers 20,000 IOPS. Bigger disk means more performance. So when should you reach for it? Enterprise applications that need reliable performance. SQL server databases that aren't massive, but still demand consistent response times. Virtual desktops where users expect instant feedback. Premium SSD handles all of that. But here's the limitation. Because performance is locked to disk size, you're stuck in fixed tiers. One more IOPS, you have to buy a bigger disk. Even if you don't need the extra storage space, that leads to over-provisioning. Paying for capacity you never use, just to get the performance you actually need. Think of it like a dependable work truck. It's reliable, it's proven, and it gets the job done. But you're paying for the whole truck even if you only need the extra payload capacity once a month. You can't just rent the truck bed for a day and leave the cab parked. That exact problem is what premium SSD V2 was built to solve. Premium SSD V2, the flexible performer. Now, this is where things get interesting. Premium SSD V2 fixes the big issue with regular premium SSD, being forced to buy more capacity just to get more performance. With premium SSD V2, you can independently adjust capacity, IOPS and throughput. No downtime, no disk swaps, just change the settings and it happens. The baseline is generous, you get 3,000 IOPS and 125 MB/s of throughput included at no extra charge. That's already more than some standard SSD disks can max out at. From there you can scale up to 80,000 IOPS and 1,200 MB/s. Plenty for most general purpose enterprise workloads. Capacity ranges from one GB/bite up to 64 TB/bites, whether you need a tiny disk for a lightweight app or a massive one for a data warehouse, premium SSD V2 covers it and the latency sub-mily second. For many workloads it's comparable to ultra-disk. Without the ultra-price tag, here's the real value. Premium SSD V2 is significantly cheaper than ultra-disk for similar performance levels. You're not paying a premium for the name. You're paying for exactly what you need. Need high IOPS but not massive throughput? Tune it that way, need lots of throughput but modest IOPS? Tune it the other way, no one size fits all package forced on you. So what's it best for? Mainstream production databases, line of business applications, any workload that needs high performance but doesn't need ultra-disk ceiling. Suicosurver Oracle MongoDB Cassandra, the databases that power real businesses, premium SSD V2 handles them all, one limitation worth noting. Premium SSD V2 is currently only available with locally redundant storage or LRS. That means your data is replicated three times inside a single data center. It doesn't support zone redundant storage yet, so if you need your data spread across multiple availability zones for higher resilience, you'll need other options or add application level redundancy. Still for most scenarios premium SSD V2 is the sweet spot. You get the flexibility to right size storage, the performance to handle serious workloads, and a cost structure that doesn't punish you for wanting better IOPS. But if your workload demands the absolute highest performance, think SEPHANA electronic health records, or real-time trading. There's one more tier to cover. Ultra-disk, the supercar. Now let's talk about ultra-disk. This is the top tier. We're talking up to 400,000 IOPS per disk, 10,000 megabytes per second of throughput, and latency measured in microseconds, not milliseconds. Microseconds, ultra-disk is built for critical workloads where you can't afford downtime. Apps that need to be fast, massive in-memory databases like SEPHANA, health record systems where doctors need info instantly, high frequency trading platforms where microseconds cost millions, AI and machine learning jobs that crunch huge data sets. Pricing is different too. Performance and capacity are separate. You pick your IOPS and throughput and pay for them separately from storage. So you can have a small disk with huge speed or a big disk with modest speed. You don't have to buy extra capacity just to get the IOPS. There's also a zone redundant storage. There are as copies your data across three zones in the same region. So if one data center goes down, your disk keeps working. That's important for the workloads ultra-disk handles. Now here's a newer feature. Instant access snapshots. It's in preview for ultra-disk and premium SSDV2. Normally, creating a disk from a snapshot takes time while data rehydrates. With instant access, you can create a disk in seconds instead of hours. And the new disk has near full performance right away. For disaster recovery, that's a big deal. You can spin up a full copy of your database in minutes. Think of ultra-disk like a Formula One racecar, incredible speed, every millisecond counts. But you don't drive a Formula One car to pick up groceries. It's built for one thing, going as fast as physically possible. And you pay for that speed. So when shouldn't you use it? For most workloads, ultra-disk is overkill. Premium SSDV2 covers 95% of cases for a lot less money. If you're not running SAP HANA or a trading platform or something extreme, you don't need ultra-disk. Start with premium SSDV2 only move to ultra if your monitoring shows you need it. So we've covered the four tiers. How do you actually choose? How to choose the right disk? So you've got the four tiers. Now how do you pick? Start with three questions. First, is it production or dev test? If it's dev test or a low traffic web server, standard SSD is all you need. Don't overthink it. It saves money and gives good performance. Second, what IOPS and latency do you need? If you need low latency and thousands of IOPS, you need premium. The question is which premium tier? If your workload is steady regular premium SSD works, if you want flexibility to adjust performance without swapping disks, go premium SSDV2. Third, what's your budget? This is where it gets real. Premium SSDV2 is cheaper than ultra for similar performance in most cases. But if you're running SAP HANA or a trading system, speed matters more than cost. Let me give you a quick guide. Dev test and web servers, standard SSD. Production with moderate IOPS? Premium SSD. Production with high IOPS where you want flexibility. Premium SSDV2. Extreme IOPS where sub millisecond latency is critical. Ultra disk. Here are some cost optimization tips that actually save money. Write size your disk from the start. Don't buy a 40 by premium SSD if you only need 500GB. Use premium SSDV2 instead of ultra when you can. It covers most cases for less money. Clean up old snapshots. They stack up and cost you. And choose LRS over ZRS if you don't need zone redundancy. LRS is cheaper and still gives three copies within one data center. One thing you don't need to worry about is encryption. ServerSide encryption with 256-bit AES is always on. It's FIPS 142 compliant. Nothing to enable, nothing to configure. Your data is encrypted addressed by default. If you need more control, you can use customer managed keys. But for most scenarios, the default encryption is enough. Before we wrap up, let's touch on a couple more features that matter for durability and security. Security, durability and snapshots. As your disk storage targets 99.9% availability thus that's 5.9s. How do they pull that off? Simple. Three copies of every piece of data. With locally redundant storage, those three copies stay inside one data center. A disk fails. Another copy takes over instantly. With zone redundant storage, copies spread across three availability zones in the same region. An entire data center goes dark. Your data stays safe encryption. Always on by default. ServerSide encryption uses 256-bit AES and meets FIPS 142 standards. That covers data addressed. But maybe you need more control. Customer managed keys let you hold the encryption keys yourself. Encryption at host goes further. It covers temp disks and disk caches, which the default encryption leaves out. For truly sensitive workloads, you can stack both. Snapshots are point in time backups. They run without slowing your disk down. The new instant access, snapshots for ultra-disk and premium SSD V2 change the game entirely. You can create a disk from a snapshot in seconds instead of hours. For disaster recovery that's massive. Spin up a full production copy of your environment in minutes. So that's the core of Azure disk storage. Build for durability, security and speed. Let's bring it all together. Four disk types. Standard SSD for budget-friendly dev and test. Premium SSD for reliable production performance. Premium SSD V2 for flexible high performance without the ultra-price. And ultra-disk for the extreme workloads where every microsecond matters. Here's the bottom line. Match the disk type to your workload. Not the other way around. Don't buy ultra-disk because it sounds impressive. Don't skimp on standard SSD if you're running a production database. Pick the right tool for the job. If this episode helped you make sense of Azure disk storage, subscribe and share it with someone starting their Azure journey. And tune in next time for another knowledge nugget.