In the modern digital age, data is the foundation of every organization. Whether it's a small business or a large corporation, there is a need for efficient and dependable data storage. And at the center of that storage system are server hard drives. They are designed to support the 24/7 requirements, heavy workloads, and optimal uptime.

Choosing the right hard drive is important for your server's performance, whether you're setting up a new one or upgrading an existing one. In this guide, we'll walk you through everything you need to know before you buy a server HDD.

Different Types of Server Hard Drives

1- HDDs (Hard Disk Drives)

Traditional spinning-disk drives have been popular in servers because they offer a high storage capacity at a lower price per gigabyte. HDDs are best suited for archiving data, backups, and other uses that don't need ultra-high speeds.

Key benefits:

  • High storage capacity at low cost
  • Stable for long-term data storage
  • Readily available in various capacities

2- SSD (Solid State Drives)

SSDs employ flash memory rather than spinning disks, with greater performance and lower latency. In server environments, SSDs are ideal for virtualization, databases, and applications that need quick data access.

Key benefits:

  • Fast read/write processes
  • Less power consumption
  • Improved shock resistance

3- Hybrid Solutions (Tiered Storage)

Most organizations employ both SSDs and HDDs to achieve a balance between cost and performance. SSDs can support active workloads, while HDDs can hold large amounts of data that aren't accessed as often.

Key benefits:

  • Scalable
  • Affordable performance

Interface Options for Server HDD and SSD:

  • SATA (Serial ATA): Affordable and best for bulk storage, backup, and archiving. Provides high capacity at the cost of slower performance. (up to 6 Gbps) 
  • SAS (Serial Attached SCSI): Used in enterprise environments. Provides greater reliability, better speeds (up to 12Gb/s), and dual-port connections for redundancy.
  • Fibre Channel / NVMe: Utilized in high-end storage networks and SANs where ultra-high-speed data transfer is essential.

Form Factor Options for Server HDD:

  • 3.5-inch Form Factor: Ideal for heavy-duty storage (20TB+ capacity), usually deployed in data centers and backup servers.
  • 2.5-inch Form Factor: Smaller, typically faster, and utilized in blade servers or when density and efficiency are important.

What to Look for in a Server Hard Drive

Performance 

When you need hard drives, these are some of the only things you need to know:

  • RPM (Revolutions Per Minute): This in HDDs indicates how quickly the platters rotate.
  • 7,200 RPM: The norm for most general-purpose drives.
  • 10,000-15,000 RPM: These are enterprise-class drives with high performance.
  • IOPS: How many read and write tasks a drive can handle in one second. It's a crucial metric for things like databases, where the system is constantly dealing with many small, random operations rather than a few large ones.
  • Latency: This is how long it takes for the drive to begin reading or writing data. SSDs and NVMe drives take far less latency than HDDs, which is the reason why they are so much faster.
  • Throughput (MB/s): This is the amount of data read or written in a second. This is the most critical metric for operations that use a lot of files, such as streaming or big data transfer.

For transactional applications such as databases, prioritize IOPS and latency. For operations that consist of the transfer of big files, you should prioritize throughput.

Storage Capacity

Server HDDs are usually between 500GB and 20TB+, depending on model and form factor. Capacity requirements depend on:

  • Type of data being stored (text, images, video, backups)
  • Growth expectations
  • Backup and redundancy strategies

It's a good idea to select slightly more capacity than required to provide for growth and particularly with RAID configurations.

Reliability and Durability

When you're running a server 24/7, reliability is everything. Here are the key specs to look at:

  • MTBF (Mean Time Between Failures): The average hours a drive is expected to run until failure. Enterprise drives typically provide 1.5–2.5 million hours MTBF.
  • AFR (Annualized Failure Rate): Lower AFR = more reliable. Enterprise drives are usually < 0.5%.
  • Workload Rating: Described in TB/year or Drive Writes Per Day (DWPD) — represents how much data the drive can write safely.

In 24/7 environments, use drives with high MTBF and enterprise-class workload ratings.

RAID Compatibility

Not all drives are made for RAID. Enterprise-grade drives are designed with better error recovery features, like TLER (Time-Limited Error Recovery). This helps keep your RAID array stable.

Use RAID-validated drives in any fault-tolerant configurations to prevent rebuild failures and performance bottlenecks.

Power and Cooling

The power a drive consumes can be quite different, particularly between idle and under load. More capacity and higher RPM drives usually consume more power and produce more heat. Consider drives with PowerChoice that offer energy savings.

If you've got a lot of servers to manage, it's an intelligent decision to opt for energy-efficient drives. Also, ensure your server is enough cooled to handle the heat.

Hot-Swap vs. Non-Hot-Swap Drives

A hot-swap drive allows you to pull out or insert a drive when the server is running, which avoids downtime. It is only possible if the server is installed with a RAID setup. Non-hot-swap drives are typical in entry-level servers. They make you shut down the whole system if you need to replace a failed drive.

Enterprise vs. Consumer Hard Drives

  • Enterprise-grade: They're designed for continuous, 24/7 operation. They possess a higher MTBF (mean time between failures), improved error correction, and generally include a good warranty. They're the standard for servers.
  • Consumer-grade: Not suitable for servers. They're less durable and aren't designed for the heavy, continuous loads or RAID arrays used in a server environment.

Maintaining and Monitoring 

  • Routine Health Checks: Periodically monitor your drives' health and performance.
  • Firmware Updates: Keep your drive's firmware updated to get the best out of it in terms of performance and compatibility.
  • Temperature Monitoring: Observe how warm your drives are operating. Hot temperatures can drastically reduce their lifespan.
  • Strong Monitoring Tools: Employ real-time monitoring to monitor your drives' condition so you can identify potential issues before they cause a failure.

Conclusion:

Selecting the right server hard drives is an investment in the performance and stability of your whole IT infrastructure. Whether you require giant HDDs for backups or fast SSDs for critical applications, understanding the features and what to prioritize will enable you to make the best decision. Always prioritize reliability, workload rating, and compatibility to ensure that your drives can do what you need them to do.

FAQs

How do SATA and SAS drives differ in server environments?

SATA is less expensive and slower (6 Gbps) and is best for storage and backups. SAS is faster (12+ Gbps), more fault-tolerant, and dual-port-capable. Best suited for demanding workloads such as databases and virtualization.

Can I use different types of HDDs (SAS and SATA) together in the same server?

Yes, if the controller supports them, but don't combine them on the same RAID array. SAS controllers have SATA support, but not vice versa. Maintain drive types in different groups for optimum performance.

Will a higher RPM provide improved performance for any application?

Not always. A higher RPM (revolutions per minute) of 15,000 RPM results in quicker access and transfer of data.