Storage on Demand: The storage technology. A comparison of HDD, SSD, and NVMe

From architecture to hardware: The right storage strategy combines performance, capacity, and flexibility through the use of HDD, SSD, and NVMe.

In parts one and two of our “Storage on Demand” series, we covered the logic and advantages of flexible storage solutions and took a look at the physical basis of the storage architectures DAS, NAS, and SAN.

In the third part, we dedicate ourselves to the storage media themselves. The choice between mechanical hard drives (HDDs), solid-state drives (SSDs), and NVMe storage significantly determines how performant, scalable, and economical a storage-on-demand system is. In this third part of the series, we highlight the differences, advantages and disadvantages, as well as typical application scenarios of these storage technologies.

Mechanical Hard Drives (HDD)

Mechanical hard drives (Hard Disk Drives) are the classic storage media and have been proven for decades. They store data on rotating magnetic disks, which are accessed by a read/write head. This technology enables large storage capacities at comparatively low costs per terabyte. This is one reason why HDDs still play a role, especially for long-term storage solutions and archiving.

The advantages of mechanical hard drives lie in their capacity and cost-effectiveness: They are well suited for large data sets that are not constantly actively used. At the same time, however, HDDs also have some limitations. The mechanical components lead to higher latencies and lower I/O performance compared to flash-based solutions. They are also more sensitive to shocks, more susceptible to wear and tear, and consume more energy.

Companies should also differentiate between consumer and enterprise HDDs. While consumer drives are mainly used in the desktop sector, enterprise HDDs are optimized for continuous operation. They offer higher reliability, longer service life and are suitable for demanding workloads where constant availability is crucial. Typical use cases for HDDs are cold storage (an archived storage of data that does not require ongoing access but must be protected in the long term), backups or large media archives, where access is rather rare.

Solid State Drives (SSD)

Solid state drives are based on flash memory and do not have any moving parts. This not only reduces the latency, but the storage media are also more robust against mechanical influences. SSDs offer higher performance with lower power consumption than HDDs at the same time.

The disadvantage is the price: per terabyte, SSDs are still more expensive than mechanical hard drives. In addition, flash cells only have a limited number of write cycles, although modern enterprise SSDs are designed for high loads thanks to optimized controllers and firmware.
Typical application scenarios for SSDs are operating systems, databases and virtual machines. Applications that require fast access or are heavily I/O-intensive benefit from the significantly higher speed. Here too, enterprise SSDs differ from consumer models due to higher continuous load capacity, more stable performance and longer service life.

A practical example: A SaaS provider stores its active virtual machines on SSDs to ensure fast response times and reliable performance, while archive data is outsourced to cheaper HDDs.

NVMe-Storage

NVMe (Non-Volatile Memory Express) is a modern storage standard for flash memory via PCIe interfaces. It enables low latencies and high data rates, significantly faster than conventional SATA or SAS SSDs. NVMe is therefore the first choice for particularly performance-critical workloads, such as real-time analytics, AI/ML applications or high-performance computing.

The advantages: NVMe drives deliver high IOPS, minimal overhead and short access times. The disadvantage is the higher cost per terabyte and the often lower maximum capacity compared to HDDs. Nevertheless, they offer a speed advantage for workloads that require it.

An example: In research centers or financial service providers, NVMe drives are used for data-intensive real-time analyses, while SSDs serve the running applications and HDDs function as a cost-effective backup and archiving solution.

The comparison

The choice of the right storage technology always depends on the application. Mechanical hard drives score with large amounts of data at low costs. In contrast, SSDs deliver stable performance for operative applications. And NVMe enables high-performance workloads with low latencies. In practice, a hybrid approach has often proven successful: HDDs for rarely used data, SSDs for active workloads and NVMe for critical high-performance applications.

Companies that use Storage on Demand benefit from the flexibility to combine these technologies as required. Workloads can be moved, expanded or reduced without physically purchasing new hardware. This not only saves costs, but also increases the efficiency and responsiveness of IT.

Conclusion: The right storage technology for Storage on Demand

There is no universal storage that is optimal for all scenarios. Workload, performance requirements, costs and capacity are decisive. The Storage-on-Demand offerings enable companies to take these factors into account and react flexibly to changes.

Companies should first analyze their workloads and then choose the appropriate storage solution. With our different Storage-on-Demand solutions, you can achieve high performance, maximum flexibility and economic efficiency.