In fact, losing even a small portion of your data is not fun. Especially, if you did not back them up for some reason. So, in today’s topic, I’d like to talk about backup storage media. I’ll review the most popular of them and give some ideas about how to pick the appropriate one for your backups.

I know that the choice of media strongly depends on the volume of data to back up, environment peculiarities, and admin’s preferences. But, while looking for the backup storage solution we all also consider some general things like price, resulting environment scalability, and media reliability. That’s what I am going to highlight today. So, today I write my ideas on how to pick the backup storage solution that may be a perfect fit for your environment.


Tapes are old… but gold, so I’d like to start with them. The idea of keeping data on tapes is not new. It appeared back in the 80’s, but after some modifications, tapes became, probably, the best media for backups. Even these days, they are actively used and developed. For a guy not from IT party, it may sound weird, but admins still use tapes. Some even prefer them over other media for their backups. We love tapes for massive capacity, durability, and low cost. Tapes allow transferring 1 TB in an hour, or so, paying just 0.01 $/GB! Also, it is pretty cheap to store data on tapes due to reduced energy consumption (typically, tapes consume 1/15 that of disks). With all that being said, it seems rather obvious why tapes are something like a universal media for backups.

However, there’s the small thing about the tape itself: it uses sequential writing. Due to sequential writing, it cannot go fast enough to compete with other media using random access.

Now, let’s look at two technologies used in manufacturing cartridges: Digital Data Storage and Linear Tape-Open

Digital Data Storage

Everyone, even guys not from the IT party, are familiar with Digital Audio Tape (DAT), recording and playback media. Later, DAT cartridges evolved into Digital Data Storage (DDS) allowing you to keep from 1.3 to 80 GB of data on the 180-m-long tapes. Actually, such tapes could be used for backups. The table below depicts DDS cartridges evolution:

New and better tapes – Linear Tape-OpenOnce being utilized for backups, the cartridges were evolving quickly. Their capacity was growing, and data transfer rates were becoming only faster. However, the amount of data to back up increased much faster than cartridges capacity. Indeed, DDS cartridges were good enough for 80’s-90’s, but they became inefficient in the 2000’s. That’s why Gen 8 cartridges were never released.

Linear Tape-Open (LTO), as it comes from its name, is another magnetic tape data storage technology. It evolved from DDS and overrode it later. LTO cartridges have been produced since 2000 and are actively developed even these days. They allow keeping tons of data, they are fast, so, they are considered so perspective.

LTO evolution is in the table below:

Optical disks

The optical disk is an optical disc data storage format. Information is recorded right on top of the disc and read with a laser later. There’s a special encoding material on top of the disc. Actually, there’s a multi-layer coating on top of the disc, but, I guess giving more details on this matter will be going into specifics.

Of course, talking about backup media, you may be a bit skeptic about optical discs as they crack and get scratched all the time. And, their capacity is not that big to compete with any other storage media. Still, they may come in handy for backing up individual local systems. I am talking not about DVDs or CDs that are good for keeping family photos, games, or movies. I’m talking about massive Blu-Ray and Archival discs that can fit up to 100 GB and 1 TB of data respectively.


  • Cheap media
  • You need just hook up an optical disk drive via USB to read/write.
  • Does not consume energy while stored


  • They can be scratched or cracked accidentally or even explode in your optical disk drive.
  • Buffer underruns are possible (disk reads much faster than data are fed). This issue brings a good risk of data inconsistency.

Find disc types in the table below:

External drives

Well, actually, there are two types of disks used in portable drives: solid state drives (SSD) and hard disk drives (HDD). I’ll talk about each of them a bit later. Drives, or external drives, whatever, come in handy once you need something faster than tapes. Sure, they are more expensive than tapes, but as time goes disks and portable devices price goes down while their capacity just keeps on growing. Unfortunately, disks are not that reliable as tapes by their design: disks are much more complicated than tapes, so the risk that the entire thing malfunctions is higher.

On the other hand, modern external drives have plenty of cool features like Wi-Fi connection, built-in card readers, hot buttons, and automatic backups. Portable devices are available both in 3.5″ and 2.5″ form factors. Note that there’s the small thing about 3.5-inch disks: they require an individual 220 V power supply. At this point, I should mention that some portable 3.5″ devices have batteries allowing you to use them, let’s say, while you are out of the office.


  • Inexpensive hot storage
  • Fast
  • Portable


  • Too expensive for archival purposes
  • The case can be broken during transporting
  • They do not scale properly, so portable drives are good only for small installations.

Solid-State Drives

SSDs keep data in semiconductor-based integrated circuits. Their capacity reaches up to 2 TB. Conventional disks form factor is 2.5″, but there also are commercial 3.5″ SSDs available on the market.


  • Long-living
  • Rocket-fast
  • Lightweight


External SSDs are too expensive. Really, think twice before buying a bunch of these things just to keep your backups


Hard Drive Disk technology is pretty old. The very first HDD was designed back in 1956 by IBM. That was a massive rack that would cost you a dime and could store only 5 MB.

Sure, modern HDDs are not that huge, and their capacity has grown dramatically. This all is thanks to increased bit density. HDDs allow storing up to 5 or 12 TB depending on the form factor.

Yet, ultra-high bit densities played a trick with HDDs durability. Magnetic field degrades, and the higher density is, the worse things become with the flow of time. And, ultra-high capacity platters are not that mature technology to feed scientists some data on how to do something with this side effect.


  • HDDs are much cheaper than SSDs, and they last longer
  • High capacity
  • Good for archives (but not that good as cloud or tapes)


  • Hard disks spin while working and their head always moves. Together, these moving parts may make some annoying noise.
  • Vulnerable to physical damages


Network-attached storage

Network-attached storage (NAS) is a computer appliance with multiple drives that are typically arranged into the RAID. NAS provides access to files using conventional file sharing protocols (i.e., NFS, SMB/CIFS, FTP, SFTP, etc.). As NAS consists of multiple disks, it ensures higher redundancy and reliability than an individual disk. And, depending on the RAID level, you can reach awesome performance.


  • Reliable and redundant
  • You can access information with any operating system.
  • High performance with the NAS (again, depending on the RAID level).


  • NASes are noisy.
  • Costs

Disk arrays

The disk array is a disk storage system comprised of multiple drives. Roughly speaking, disk array may be considered NAS but with more disks on board. Well, that thing is what cloud providers usually use.


  • Disk arrays have high performance
  • Redundancy and fault-tolerance.


  • Require cooling
  • Noisy
  • Significant energy consumption

Cloud Storage

Sure, you can use an on-premises environment to keep backups or send your tapes, disks, or external drives out of your main site. Or, you can find guys who will keep the data for you! That’s, actually, what public cloud providers do. To date, there are many public cloud providers (i.e., Microsoft Azure, Amazon Web Services, Google Cloud, etc.) that readily provide you with rock-solid storage for your backups. Which provider to choose is up to you, but here’s an article discussing which one is the cheapest.

Also, you can go even further and keep backups in multiple cloud storages. That makes data availability even higher. Sure, you may need dedicated software to offload and manage your data, so here’s the article discussing such solutions.


  • High redundancy
  • Safety
  • There’s no need to buy hardware dedicated for backups


  • You depend on cloud providers
  • Prices may grow.

So, which backup storage solution should I chose?

Sure, there is no universal solution. But, here is some advice on how to pick the one based on your IT environment:

  1. First, decide on the data you are going to back up. It can be a single file or your entire environment. It can be your VMs, physical servers, databases, etc. The data you intend to back up predetermines the solution you should use.
  2. Next, think through how reliable the media is. You do not want to lose your entire database due to accidental optical disk explosion in your optical drive device, right?
  3. Think how scalable and fault-tolerant the resulting infrastructure is.
  4. Do not forget about redundancy. If one copy is gone, that’s nice to have an extra one! At this point, I want to remind you Veeam’s 3-2-1 backup rule: keep 3 copies of your data on two different media with one copy off-site.
  5. Come up with the retention In other words, decide on how long you may need your copies.
  6. How many data over that period of time will you accumulate?

Looking at some cases

Now, let’s discuss some scenarios. Hope, they help you to pick the right backup storage for your needs.

1. There’s a small environment and the retention period is 6 months. Each month, 100 GB of backup data arrive.

Obviously, your backup storage should keep 600 GB data. There are two possible solutions: a couple of HDDs (external drives should also work out), or public cloud storage.

Keep in mind that the resulting solution should be redundant. That’s, actually, why you need at least two HDDs or external drives. In the backup “environment” like this (if you can call it so), one disk is used as the backup storage, while the second device keeps one more copy of data. Should the main disk with backups malfunction, or be lost, you always have an extra copy of your data!

Well, disks are good, but they are still on your main site! Should something go wrong, all your precious data are gone. Actually, that’s why it may be a good idea to use the public cloud. Paying a few cents per-GB in the cloud, you can achieve higher fault tolerance and data safety. Who knows, you may even save some money!

Of course, you can pick both! That makes your data even more redundant.

2. There’s a medium environment and the retention period is 6 months. 1 TB of data arrives each month.

Well, after doing some quick math, it becomes obvious that your backup storage will grow to 6 TB in 6 months. Well, that takes you a while to restore so much data. So, you should choose NAS, tapes, or cloud storage. Let’s look at each option now.

NAS seems a cool solution to keep all that data. It is reliable and fast, but it may turn out a way too expensive for you.

Alternatively, you can use tapes. They are cheap and can easily last a decade. However, tapes aren’t that fast as storage media using the random access. Really, you can easily get out the backup window one day. Also, tapes have their scalability limited by the capacity of the format. So, businesses using tapes may end up looking for new formats.

Looking back at two solutions mentioned above, public cloud may be a perfect fit. It enables to keep your backups off-site for a modest price. And, you should not maintain a dedicated environment! Well, sure you still can keep some frequently accessed data on-premises on disks leaving the rest for public cloud.

3. There’s a huge environment and the retention period is 6 months. You have 10 TB to back up each month.

In this scenario, you will end up with 60 TB of backups at the end of the retention period. Wow, that’s a huge amount of data, and you need a really fast backup infrastructure that won’t be hectic in management. Well, if I were you, I would consider disk arrays, tapes, or public cloud storage, or at least two of these media to keep my backups.

Disk arrays are fairly expensive, they heat and consume a lot of energy. On the other hand, they ensure data redundancy you may be looking for. So, if you need that much data on your site, a disk array is a perfect fit.

Tapes may be another solution. But, really, do not rely on them that much. They are fairly cheap, it costs you nothing to store them, but they are far too slow.

If you need fast storage without paying a dime, use the public cloud. It is fast, and it is not that expensive as a disk array. Furthermore, you won’t be the guy who should maintain the backup environment!

As for me, it is always better to keep one copy in the house and one somewhere else. So, why don’t you combine, let’s say, disk arrays and public cloud? Well, if you do not have a budget for that and can tolerate waiting a while, go tape.


Today, I discussed backup storage solutions you can use for backups. Chose the one based on your needs, environment, and budget. As you probably have noticed, I prefer to keep my backups in public cloud. You may also want to keep your backups there, but, again, it is not a universal backup media. So, think through your needs and expectations. Of course, you can combine storage media. By doing that you will achieve even higher data redundancy, so you’ll always have an extra copy of data.