and seem like tag synonyms to me.

I would prefer online-storage to be the master (19 questions), because it is more generic, though cloud-storage has more questions (about 74).

Agree, disagree?

My opinion after reading some of the rather passionately written answers:

Though cloud-storage and online-storage may not have the same textbook definitions, I find it safe to say that users who frequent SU do not give a hoot about these definitions. When they talk about online- or cloud-storage, they mean stuff like Dropbox, Wuala, SkyDrive, WebDAV and whatnot. Actually, so do I. I don't see a point of having two different tags for two things so similar.

May I remind you of the purpose of tags:

A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

In the interest of simplicity, I move that the two be made tag synonyms.

  • 10
    But online-storage contains 100% fewer buzz words!
    – rtf
    Commented Jan 21, 2014 at 15:23

6 Answers 6


For all practical purposes they are the same thing. In "cloud storage" the "cloud" is the Internet. Online storage also generally refers to storage on an Internet-accessible storage device. Alhough cloud-storage seems to impart the connotation of something with a more modern app- or web-based interface, consumer storage vendors market their Internet-accessible external hard drives as cloud storage, whether they use an older protocol such as FTP or a new-fangled web-based interface. So I personally would consider them synonyms.

  • Though, do you support a merge, if so, which should be the master?
    – Thor
    Commented Jan 21, 2014 at 14:23
  • 9
    Yes, I would support a merge. I think online-storage should be the master since it is timeless. Cloud-storage is a hip buzzword for the same thing.
    – rob
    Commented Jan 21, 2014 at 18:05
  • I agree, thanks for clarifying.
    – Thor
    Commented Jan 21, 2014 at 21:01

There is a difference.

The online storage can go offline, thereby being risky. Obviously no one wants that!

The vendor could go out of business. I don't want that!

Their disks could fail or their data-center could get hit by earthquake, power failure, their techies walking out, getting hired by competitors, their VC funding could get pulled, someone going berserk and causing criminal damage on their RAID arrays. Yikes! I for sure don't want that!


The cloud storage is fuzzy.. fluffy.. and if you don't live in Seattle or Portland, it is related to feeling good instead of bad and depressed. I want that!

It is also related to fluffy white angels flying around waving magical fairy dust over all that ails humanity, so your data is always healthy and in a magical land. I sure want that!

It is also related to contents of a pillow so it represents cushioning properties. This means whenever there is any kind of bump, my data will be cushioned in a fluffy cloud and would be saved from any harm. If I'm an IT manager I will also sleep well at night thinking my data is not on a hard drive but on a soft pillow! So I want that too!

What happens behind the cloud is mysterious yet somehow I am hypnotically suggested to not even think to question or look inside it. I definitely never question, if it's stored on cheapest drives possible without any protection like, RAID or backups, environmental, power supply redundancies etc. etc. I simply avoid all these questions and the headaches they cause. O boy! I want that! As a result this also means more customers, lower costs and higher profits for the "storage provider" by just changing a label, so they definitely want that!

In summary, online v/s cloud = storage no one wants v/s storage everyone wants.

My personal view of this... Meanwhile, all of us techies (myself included) focusing immensely at discerning the differences in the wording of what are obviously synonyms due to common usage, busy looking for all of the subtleties, get to marvel and discuss and clarify and debate, deriving multiple types of cerebral highs in the process from inane stuff, as if our heads weren't already full enough with it. Of course, we want that!

Stackexchange gets to have more traffic even though the content borders on inane, hence incrementally more ad revenue. Is a no brainer that they want that! Note: on "no brainer" I am using the word inane, in it's more obscure reference i.e. about the brain and not no brain. On this, please do not take offense and instead give me your understanding. I want that!

Finally search engines get excited and all the machines kick in having more to link and sort and sift and index more keywords on many of their criteria. I bet they want that!

Seriously, if someone reading this actually gets to take a humorous or sarcastic or questioning look at what we are doing with our brains.. I'd consider that enlightening and I personally want that! :-)






  • 1
    We get it... You want things. :P
    – user402879
    Commented Jun 9, 2015 at 16:35

They both can be considered synonyms.But Cloud storage is referred to a system where the storage is distributed. The files are not stored in a single location but a collection of nodes together save the files.Cloud storage is a type of Online storage.

  • 1
    Yes, traditional non-distributed online storage is not cloud storage, so the two terms are not technically the same.
    – depquid
    Commented Jan 21, 2014 at 17:36

NO, they are NOT synonyms.

The "Online" in Online Storage refers to the AVAILABILITY of the storage, not it's mode of access or location.

Cloud Storage is a type of Online Storage:

Storage Availability generally comes into 3 camps:

  • Online Storage:

    Is storage that is already "mounted" and accessible immediately (there may lag or delays inherent in the system, but there are no prior steps required to "prepare" the storage. Examples would be a local hard drive, a plugged in USB drive, a plugged in external hard drive, a CD/DVD in the drive with raw file system files that can be seen and accessed through the file system at the moment (the drive has already been mounted), network storage (file servers, NAS, SAN, and Cloud Storage)

  • Nearline Storage:

    Is storage that needs to be first mounted (sometimes by a system administrator) in order to be accessible. Examples include a USB or external drive not plugged, a Virtual Drive that must be loaded or mounted by a Virtual Manager like HyperV, VMWare, or Oracle's VirtualBox, a backup "Image" of partition or drive created by something like Ghost, or Acronis, a .IMG or .ISO file image of a CD/DVD created with burning software that you then MOUNT as online storage (if you use it to BURN a DVD/DVD... then you are RESTORING a BACKUP and in this way, it is Offline Storage)

  • Offline Storage:

    Is storage that resides in a backed-up form. That is, it's usually compressed, possibly encrypted, and possibly contains only the DELTA (changes) from the last backup. These techniques are ll part of Storage Management strategies and solutions that make point in time snapshots and rolling backups possible, timely, affordable and therefore feasible.

    However, the data stored CAN NOT accessed in this backed-up form. It must first be RESTORED to either Near-line Storage (then mounted) or Online Storage

How They Work [Together] In Practice

None of above terms (Online, Near-line, or Offline) necessitate actual Cloud Storage... which is what an end-user interfaces with, whether with a web page/web GUI, or an API, or a desktop app that allows syncing and access through the PCs file system). Cloud Storage data may be stored in one or more physical locations (e.g. datacenters) with pipes to the Internet

In Enterprise systems which constitute more than 80% of all data in actual storage, these concepts are staples as all Enterprises with large data needs, including Cloud Storage Provider like DropBox, or Box.net, or Google Drive all must manage their Storage for either internal and/or external use (as the Storage as a Service product/service that they provide to their customers).

Therefore, all enterprises use some combination of Online Storage, Offline Storage, and Nearline Storage on their "back-end" to manage, serve, and backup/ensure service continuity.

In addition, a Cloud Storage Provider might have 1, 2, or all 3 forms of storage as part of a Storage Management strategy that allows the provider to do business... in his case, PROVIDE Cloud Storage.

As far as the consumer is concerned... this Cloud Storage is online (because it's "immediately available" as long as it is available through his file system (with the use of a syncing desktop app) or even in an app or web interface, so long as that is the primary interface with which the user gets to all his files e.g. the user primarily uses a web browser/web apps (either on desktop, or they only have a Chromebook, let's say) to do work, such as Google Docs to create documents and stores and retrieves them on Google Drive or DropBox.

But, once again, in order for the Cloud Storage Provider to provide the data Storage As A Service, he may need to employ 1-3 forms of Storage (Online, Nearline, and/or Offline).

  • 1
    This is what I was going to post; the online in online storage has nothing to with the Internet. Commented Jan 30, 2014 at 5:12

Provisioning storage is a basic public cloud feature. The provisioned virtual storage is provisioned off the local system, and off the LAN, thus is also an online storage. (But online storage can be hosted on a cloud or using legacy technologies.)

Online storage refers to the fact that something is not local, but accessible thru a connection, here via the Internet. How data are then actually stored is not part of the online concept, and neither is the protocol used to access remote data. As soon as data are stored off the local computer, we can talk about online storage, especially if this is also off the LAN (else "network storage" is more usual).

Some points of reference about cloud computing

There isn't (yet) an agreed definition for what is cloud computing. Cloud is still basically a marketing word, barely a new concept. Some previously known mechanisms are typically used for the cloud concept: virtualization of CPU, RAM, storage and network, and clustering. VMWare is a good example of resource virtualization manager on x86 platforms (the name often used is hypervisor). Long before VMWare, IBM invented VM-CP which has the same intent.

Physical storage can be virtualized using a storage hypervisor.

An hypervisor can be configured to manage multiple physical resources (CPU, RAM, storage, network) on different physical platforms, even different LANs.

As soon as everything is virtual, then it is easy to create copies of virtual machines, virtual networks and virtual storage. It is also easy to create virtual resources on a pool of physical resources. Easy duplication allows for implementing quick backup, and restoration of a stored virtual resource is possible on another hardware under the control of the supervisor. This allows in turn to move virtual resources between the physical systems of the pool in case one goes down or is overloaded.

Creating a new resource can be done from an image of a machine (with predefined OS, middleware, and applications). Different images can coexist to create different virtual resources. Depending on what is part of the image, there are simple virtual machines without OS, with OS, with OS and middleware, with OS, middleware and applications, etc. Virtual machines are commonly referred by their somehow agreed types: IaaS, PaaS, SaaS (infrastructure, platform, software... as a service). Typically these resources are rented for a monthly fee to public (shared) or private (dedicated) cloud providers and paid "as a service" as long as they are used.

Creating resources can be done using a simple interface, typically a web page, and the management of the virtual resources can be delegated to the end user. Creating a new virtual resource is called "provisioning".

Today using a cloud commonly refers to the capability for the user to provision resources that exist on one or several physical platforms across a LAN or a WAN.

The idea that when it is "on the cloud" then you cannot know exactly where it is, because it is moving depending on current system load and failures, is not exact. Many forms of cloud solutions for enterprises are typically implemented on dedicated hardware (e.g. private clouds located somewhere, sometime just hosted in the enterprise premises and connected to the LAN.


They are exactly the same thing. "Cloud storage" as it has come to be known in recent years is just a modernized term for "Online storage." I do not know how or why online storage has been replaced with cloud storage, as online storage more accurately and professionally describes this type of storage.

  • Not sure. Cloud storage implies some virtualization and provisioning. Online storage can be everything remote. I added an answer to develop the idea.
    – mins
    Commented Jan 26, 2014 at 23:11
  • That is absolutely incorrect. In Enterprise systems which constitute more than 80% of all data in actual storage, there is Online Storage, Offline Storage, and Nearline Storage. None of these necessitate actual Cloud Storage... which is what an end-user interfaces with (whether with a web page/web GUI, or an API, or a desktop app that allows syncing and access through the PCs file system). Commented Jan 27, 2014 at 15:25

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