AZ-104 Certification Notes

Chapter 10.5 - Disk Types

Azure Disks - Disk Types

Azure offers 4 tiers of disks:

1. Ultra Disks
   • Deliver high throughput, high I/OPS, and consistent low latency disk storage for Azure VMs
   • Dynamically change the performance of the disk, without the need to restart your VM
   • Suited for data-intensive workloads such as SAP HANA, top tier databases, and transaction-heavy workloads
   • Can only be used as data disks (use a Premium SSD or OS Disk)
   • Only supported with very specific VM series
2. Premium SSD
   • High-performance and low-latency disk support for Azure VMs with input/output (IO)-intensive workloads
   • Suitable for mission-critical production applications
   • Only be used with VM series that are premium storage-compatible
   • Guaranteed IOPS, and throughput of that disk (Standard tiers don't have IOPS guaranteed)
   • Designed to provide low single-digit millisecond latencies and target IOPS and throughput described in the preceding table 99.9% of the time
3. Standard SSD
   • Cost-effective storage option optimized for workloads that need consistent performance at lower IOPS levels
   • Compared to standard HDDs, standard SSDs deliver better availability, consistency, reliability, and latency
   • Suitable for Web Servers, low IOPS application servers, lightly used enterprise applications, and Dev/Test workloads
   • Designed to provide single-digit millisecond latencies and the IOPS and throughput up to the limits described in the preceding table 99% of the time
   • IOPS and throughput may vary sometimes depending on the traffic patterns
   • Available on all Azure VMs
4. Standard HDD
   • Reliable, low-cost disk support for VMs running latency-insensitive workloads
   • Available on all Azure VMs
   • Latency, IOPS, and Throughput of Standard HDD disks may vary more widely as compared to SSD-based disks
   • Designed to deliver write latencies under 10 ms and read latencies under 20 ms for most IO operations
   • Available in all Azure regions and can be used with all Azure VMs

Practice Quiz

• Which Disk Type has reliable, low-cost disk support for VMs running latency-insensitive workloads and is available on all Azure VMs?

  • Standard SSD
  • Standard HDD
  • Ultra Disks
  • Premium SSD

• Which Disk Type has high-performance and low-latency disk support for Azure VMs with input/output (IO)-intensive workloads and is suitable for mission-critical production applications?

  • Premium SSD
  • Standard SSD
  • Standard HDD
  • Ultra Disks

• Which disk tier can deliver high throughput, high I/OPS, and has consistent low latency disk storage for Azure VMs?

  • Ultra Disks

• What is Standard SSD?

  • It is a cost-effective storage option optimized for workloads that need consistent performance at lower IOPS levels. Compared to standard HDDs, standard SSDs deliver better availability, consistency, reliability, and latency.