1-Before You Buy Your Synology NAS

When you plan to buy a network-attached storage or NAS device for your home or small business network, you can ask yourself a few questions.

This is the first part in a series on getting started with your NAS: pre-sales advice.

Before You Buy Your Synology NAS

First, what information do you intend to store on your NAS? Do you plan to put your photos, videos, and other media collections on the NAS? Will the NAS become your private cloud with files synchronized between devices and accessible anytime, anywhere? Or is the NAS intended as cold storage for finished projects?

You can also use your NAS as a central backup location of all computers in your network or at the center of your video surveillance.

More uncommon but not very exotic uses are a website, a virtual machine, or an Office suite for the company, running from your NAS.


A Synology DiskStation comes with a large bundle of applications. Note, however, that smaller devices in the budget line support fewer applications. Examples are Active Backup for Business, Virtual Machine Manager, and Synology High Availability, to name a few.

Active Backup for Business is a great tool that lets you back up your computer to your NAS. Look for a NAS model in the Plus series to get support for that.

The same applies to the Virtual Machine Manager. This tool lets you run virtual machines on your NAS. It would be best to have more RAM and a more powerful processor, not available in budget line models.

Amount Of Storage

Obviously, the NAS could serve multiple purposes. But whatever your intentions are, you have to consider two things.

First, what is the amount of storage that you need now and in the foreseeable future? Do you estimate data growth? A rule of thumb for assessing the amount of storage is that you double or triple the current required amount to allow for expansion.

Second, does the NAS offer the software to enable your intended use? The suggestions I gave here are all within the standard software capabilities of almost any Synology NAS model.

What is your projected lifespan with your NAS purchase? Three years, or five, or maybe ten? Calculate the required space accordingly.

Storage Expansion

Note that you can expand your Synology DiskStation in the future in several ways.

First, when purchasing a multi-bay DiskStation, you do not have to fill up all drive bays initially but use a few now and add more later.

Second, some models support the use of one or more expansion cabinets. This cabinet is a box similar to the DiskStation, that can house several drives and connect to your NAS. You still have one NAS but with additional drive bays.

Third, you can replace disks one by one with ones with a larger capacity without the need to reinstall data if you have a redundant disk set.

Fourth, with Synology, it is easy to migrate to another DiskStation. You put the disks from your current NAS into another, typically newer, model with more drive bays, and start from there, adding new drives.

Number Of Drives

NAS devices can combine multiple drives into a single larger volume. They are also capable of establishing redundancy on the drive level. This means that one drive, or sometimes even two, can crash during operation without losing data.

Redundant disk configurations are highly recommended. To assess the drive capacity you need to buy, you factor in both the required total storage and redundancy levels. Two examples may explain this.

A setup with two drives of 8 TB each, paired in a mirroring configuration or RAID 1, sacrifices the capacity of one drive for redundancy. The total amount available is 8 TB.

Another set up with three drives of 4 TB each, combined in a RAID 5, sacrifices the capacity of one drive for redundancy. The total amount available is 8 TB.

For an overview of RAID levels and different comparable SHR configurations see also the Synology RAID calculator.

Number Of Volumes

You can combine multiple drives in different (redundant) configurations or storage pools. On these pools, you create one or more volumes. A volume is what the applications see. Some applications can store their data on a specific volume. This way, you can balance the load between drives or pools of drives.


This is a simple question to answer. HDDs offer much more storage capacity per dollar/euro, where SSDs are totally silent and generate less warmth. A low capacity and always-on setup would greatly benefit from SSD. In general, HDDs are most used in NAS storage. Note that there are special models of HDDs and SSDs for NAS usage.

Amount Of Memory

Apart from the hard drive capacity, you can expand the preinstalled RAM or random access memory, just like in your computers. The preinstalled capacity is most of the time sufficient for basic use like file storage. Some applications require more RAM. You can always add more RAM later.

Note that the budget line of DiskStations does not (always) support memory expansion. You are advised to use a Plus model for memory expansion.

SSD cache

More and more models provide space for optional SSD cache memory modules. These modules are not used for permanent storage, like SSD or HDD, but act as a fast buffer that lets you write or read data quicker to and from your HDD.

This is in particular helpful if you have repeated read requests. The cache stores that last retrieved data and can deliver that quickly again.


Like any computer, a NAS has a main processor. Do not underestimate the need for a sufficiently powerful processor on a NAS. Quad-core processors are now more common than 2-core models and for a good reason.

Note that you can not upgrade the processor like you can do with RAM or disks unless you buy a new NAS.

Synology DiskStations come with different kinds of processor brands.


Proper network connectivity is paramount for good performance. Some models offer multiple network ports that can help. You connect your NAS preferably with wired Ethernet to the network instead of WiFi if possible.

Protect Your Eggs

Whatever NAS you buy, it has only one disadvantage. Putting all your eggs in one basket is risky. The same is true for putting all your data on your NAS. Unless you protect it, there are two measures you can protect your data.

The first most people think of is a backup. Yes, you have to backup your NAS. You typically backup your NAS to another NAS, preferably in another location or an external hard drive. But backing up to a cloud service is a good idea too.

Synchronization is another way to both secure and distribute your data.

The second way to safeguard your data is to assure that your NAS is always connected to a pure and uninterrupted power source, without surges and spikes. There are devices for that, named uninterruptible power supply or UPS for short.

A UPS filters the power source and feeds a clean signal to the NAS. Short outages are mitigated with their battery power. And in case of a longer period of power downtime, the NAS is automatically shut down by the UPS.

Why Synology

When you consider a NAS, I suggest you review the offerings from dedicated NAS builders. Many NAS devices from disk manufacturers (like WD) or component collectors (like LaCie) do not have a real understanding of what a NAS is and what a user needs.

A NAS is a computer, a server, hardware, and an operating system, just like Windows or macOS on your computer. It needs support, updates, and more. Real NAS builders do this maintenance and research, and Synology is one of the bigger players in the market. Their support is good, and offered functionality out of the box is outstanding. They have a broad line of models for every need and budget.

Synology Models

When you visit the Synology website https://www.synology.com/en-global you are easily overwhelmed by the sheer amount of models. You will notice terms like the Plus series, Value series, and even the J series. In general, the Plus series are better specified and will offer you more value in the long run. You can buy 2, 4, 5, 6, or more bay models, determine the number of disks you plan to store in the device.

Advantages of Plus (+) models compared to standard (value) models:

  • 3 years warranty and extendable to 5 years; 2 years for basic models except for DS220+
  • more applications, like Active Backup series, Virtual Machine Manager
  • more RAM (standard and expansion)
  • more powerful processors

Different Models

Explain the naming scheme Synology uses for their models [to do]

More On RAID Configurations

On a Synology NAS, you can combine multiple disks into a storage pool. You either combine all storage but lack redundancy, or sacrifice a part of your storage for redundancy.

Redundancy means that a disk, or sometimes even two, may fail without loss of data. In addition, after replacing the failed drive and rebuilding the RAID, you remain up and running. Last but not least, when you replace your disks on a one-by-one basis with intermediate rebuild with a larger capacity drive, you end up with an array of larger capacity.

Note that a Synology DiskStation with one drive bay has a basic partition scheme that does not support any form of RAID.

Common RAID Types

Except for the RAID 0 type, it is assumed that all drives have the same capacity for simplicity. In case capacity differs, the lowest capacity counts. Apart from the common RAID types, a Synology NAS also offers the more flexible SHR and SHR-2 types.

RAID types that are common are:

  • RAID 0
    or striping is fast
    combine all drives, remaining 100% capacity, no redundancy; requires at least two drives
  • RAID 1
    or mirroring is resilient
    combine two drives, remaining n-1 capacity, redundant against loss of one drive
  • RAID 5
    or striping with parity is resilient
    combine three or more drives, remaining n-1 capacity, redundant against loss of one drive
  • RAID 6
    combine four or more drives, remaining n-2 capacity, redundant against loss of two drives
  • RAID 10
    is a combination of RAID 1 (mirroring) and RAID 0 (stripping) and therefore fast and resilient,
    combine four or more drives but an even amount, remaining 50% capacity; redundant against loss of half of the drives

Note: it seems you can migrate RAID 5 to RAID 6.

SHR types are more flexible because they change the RAID type when more drives are added without reformatting.

  • SHR
    with two drives, SHR works like RAID 1, and with three and more drives like RAID 5; remaining n-1 capacity, redundant against loss of one drive
  • SHR-2
    requires four or more drives, SHR-2 works like RAID 6; remaining n-2 capacity, redundant against loss of two drives


An alternative for RAID 6 or SHR-2 is SHR or RAID 5 with one spare drive on the shelve. You can migrate SHR to SHR-2 without problems from the Storage Manager.

In part 2 of this series, we continue with the hardware setup.

Thanks for reading

This post is donation-ware, and I made it to help you. Please consider leaving a comment or buying me a coffee if it did. I will be eternally grateful.

Paul Steunebrink / Storage Alchemist

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