Network Attached Storage (NAS) with Hard Drive

What to Consider When Buying a NAS

QNAP TS-251, 2-bay NAS with Intel Celeron Dual-Core CPU – $276. Check Price at Amazon

Do you need a network attached storage (NAS) device for your home or small office? A NAS is a purpose-built storage server that conveniently plugs into a switch or router on your LAN through a Gigabit Ethernet port. Buying a NAS can provide many benefits, including always-on access to your files from anywhere, high quality streaming of media files, backup, and redundancy to protect your data.

Many people prefer to stay in control of their data, rather than uploading it to public cloud storage such as Dropbox or Google Drive. Besides, the monthly fees for those services can add up over time, especially if you’re storing a large volume of data. If you go for a NAS targeted at high-end consumers or SMB, you can take advantage of powerful features which may include:

  • Multi-Platform Support – Access your files from operating systems including Windows (SMB), Apple Mac (AFP), Linux (Samba), WebDAV, FTP, iOS and Android apps
  • Security & Encryption – Set up multiple users with access permissions for individual files and folders on your NAS. Securely access your data beyond the LAN with end-to-end encryption through a cloud service, VPN or SSH FTP (SFTP).
  • Streaming Music & Video – Torrent multimedia files directly to your NAS, eliminating the need to leave your desktop torrent client open, then stream in up to 1080p or 4K quality to any device (transcoding)
  • Mirroring & Replication In a multi-bay NAS, replicate data between drives in a RAID array to prevent data loss from a drive failure
  • Off-Site Backup – Backup your data to another NAS (or public cloud) off-site, in case of a theft, natural disaster, or any event that results in physical loss/damage of the drives
  • Virtualization – Deploy Windows, Linux, Android and Unix virtual machines on your NAS using the built-in hypervisor and remotely manage them from any desktop.

When buying a NAS, most users consider these vendors who are among the most prolific in the home NAS / SOHO NAS space: Synology, QNAP, Asustor, Buffalo, Seagate or Western Digital.

If you want a NAS that can do most (or all) of the things above, here are the features you’ll want to look for at a minimum:

Intel Atom or Celeron Processor

The more inexpensive NAS devices are powered by ARM processors, which are low-power chips much like the ones found in your smartphone. For a personal NAS that will only be accessed by one or two people at a time, an ARM-based NAS like the Synology DeskStation DS216J with a dual-core Marvell processor is perfectly fine.

On the other hand, if the NAS is for multiple users who will be streaming HD video or transferring large files simultaneously, choosing an Intel-based NAS like the QNAP TS-251 or TS-451 makes a huge difference to the download/upload speeds. Anything below an enterprise-grade NAS will typically have a dual or quad-core Intel Atom (low power, more economical) or Celeron (faster, better transcoding) processor.

Multi-Bay Support for RAID

Whether you choose a 2-bay or 4-bay NAS depends on the capacity and what RAID configuration you need to achieve your fault tolerance (mirroring) and performance (striping) objectives. You can use additional bays either for additional storage or replication.

Most home or SOHO NAS are 2-bay models configured for RAID 1, which provides 1:1 mirroring so you won’t lose data if one of the drives fail. The trade-off is you can only use 50% of the total capacity of the drives.

Example: A 2-bay RAID 1 NAS with two 2 TB hard drives (4 TB total capacity) has 2 TB usable capacity. Without RAID, all 4 TB can be used but you might lose data if either of the drives fail.

For a 4-bay NAS configured in RAID 6, 50% of the total capacity will be usable but the setup can tolerate up to two of the drives failing without losing data. If the same NAS was configured in RAID 1, up to three of the drives can fail without ill effects.

Diskless vs Populated NAS

Most mid-range to high-end NAS devices ship diskless, meaning that the NAS itself is just an enclosure and the hard drives are purchased separately.  Cheaper, single-bay personal NAS usually ship with the hard drive (HDD) included, also known as a populated or diskful NAS. 

This may seem like a convenience, but beware that the HDD’s interface (connector) is soldered onto the enclosure’s logic board, making it impossible to upgrade the capacity of your NAS or replace a failed drive. Storage geeks call these “frankendrives”, describing storage vendors’ tactic to push users into buying a new NAS altogether when the HDD needs replacing.

Many NAS have drive bays that can be swapped directly from the front of the device, while other models need a screwdriver to disassemble the chassis. Some even support hot-swapping, which means that a failed drive in a RAID array can be replaced without powering the NAS down.

As an average user, you won’t need to replace the HDDs too often but ease of [physical] access can be a consideration. There are also a few designs feature locking drive bays that can only be slotted out with a key, if physical security is a concern.


Best Hard Disk Drives for NAS

WD Red NAS Drive
WD Red 3 TB NAS HDD – $109. Check Price on Amazon

Once you have purchased your NAS, you will need to fill it with the appropriate HDDs (assuming bought diskless). Like most other servers, your NAS probably takes any hard drive with a SATA interface. Before you throw the cheapest desktop drives you can find into your NAS, bear in mind there are NAS specific HDDs.The oft-asked question is: Are they worth the extra cost?

Using hard drives in a NAS places more wear-and-tear on their internal components compared to in a workstation. Hard drive reliability is measured by an industry metric called MTBF (Mean Time Before Failure). NAS drives are typically rated for a lifespan longer than ordinary HDDs. The difference can be as much as 750K hours for a desktop drive versus 1M hours for a NAS drive. Usually, you also get a longer warranty period of 5 years from the manufacturer.

In addition, NAS drives are built for higher performance compared to their desktop counterparts. HDD speed is often a bottleneck that affects the overall read/write performance of your NAS. By choosing a NAS drive that operates at 7,200 RPM or greater, you can make sure your hard drive isn’t what’s slowing your NAS down. Regular desktop drives that operate at 5,400 RPM can be agonizingly slow, especially when used in a RAID array.

What about a Solid-State Hybrid Drive (SSHD) or Solid State Drive (SSD)?

We can recommend neither for a consumer-level NAS. The SSHD technology developed by Seagate relies on a small SSD cache to accelerate the performance of a mechanical hard disk. While effective in caching startup files and frequently accessed applications on a desktop, SSHDs have a negligible performance benefit when used in a NAS.

Although fast, SSDs are problematic for NAS servers because they have limited read/write cycles, leading to premature wear. You could go all out and spend your money on server SSDs (which use higher quality NAND flash for greater longevity), but it would be in vain for a NAS that’s limited to 1,000 Mbps on Gigabit Ethernet (1GbE). To get the full benefit of the SSDs’ speed, you would need to upgrade to an enterprise-grade NAS that supports a 10 Gigabit Ethernet (10GbE) connection.

In conclusion, if you purchase a mid-to-high-end NAS, your best bet is to purchase NAS-optimized hard drives to make the most of your investment. Popular products include the WD Red, Seagate IronWolf and HGST DeskStar NAS drives.

Featured image used under Creative Commons License, courtesy of Sinchen Lin

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