What is a Secondary Storage? Types, Purposes, and Examples

September 1, 2023,

Understanding the different types of storage, particularly secondary storage, is crucial not just for tech enthusiasts but anyone who uses a computer. Whether running a business, safeguarding personal photos, or storing important documents, secondary storage options can provide the security and capacity you need.

Understanding Secondary Storage

Secondary storage, different from primary storage used on devices, acts as a vital backup, an archive, and an extended storage area, safeguarding our data and ensuring its longevity.

In this guide, we’re taking a close look at secondary storage. We’ll break down its types, explain its role, and share real-life examples to show just how crucial it is.

What is the Definition of the Term 'Secondary Storage'?

When people ask, “What is a secondary storage?” they often refer to a category of non-volatile storage devices that can be internal or external to a computer system. 

Secondary storage is a supplementary data repository that complements a computer’s primary storage. It facilitates long-term data preservation and offers a cost-effective solution, although it may sacrifice speed in data retrieval compared to primary storage.

If the primary storage fails, then the secondary storage can be used to recover the primary data. 

Understanding What is RTO and RPO can help you further appreciate the importance of secondary storage in maintaining business continuity.

What is Stored in Storage Devices?

We can divide data in secondary storage devices into three categories:

  • Backup Data: Refers to duplicates of information from the primary storage, and this type of data safeguards against potential losses that may arise from mishaps, system failures, or fraudulent activities. When necessary, users can reintegrate this data into the primary storage.
  • Archival Data: Comprising information no longer essential for routine operations but is required for legal, historical, or compliance stipulations. Transferring such data to secondary storage allows for space conservation and performance enhancement in primary storage.
  • Cold Data: Refers to information that is seldom accessed or modified but still holds value or potential for future use. This data type is best stored in secondary storage devices with low operational costs and high storage capacity, albeit with reduced speed and performance. All S3 cloud providers provide cool storage.

Why Do Computers Need Secondary Storage?

Secondary storage complements primary storage by providing an area for data that doesn’t require immediate or frequent access. This migration alleviates the storage burden on prior devices, improving their performance. For businesses, this is a key element in a comprehensive Business continuity vs disaster recovery strategy.

What is the Purpose of Secondary Storage?

Secondary storage aims to provide a reliable, enduring, and economically viable medium for retaining data beyond the capacity constraints of primary storage.
It serves as a contingency measure against primary storage malfunction or data corruption.

It enables advanced functionalities such as data analytics, sharing, and collaboration by permitting data access across multiple devices and geographical locales.

Examples of Secondary Storage Devices

Commonly encountered examples of secondary storage devices include:

  • Hard Disk Drive (HDD): Offers high storage capacity but has compromised speed and higher power consumption disadvantages. These can be internal, external, and networked options (NAS).
  • Solid State Drive (SSD): Offers high data retrieval speeds but has restricted storage capacity. To understand how reliable are SSDs, you can read more here.
  • Thumb Drive: Moderate data retrieval speed and storage capacity.
  • SD Card: Moderate data retrieval speeds and storage capacity.
  • CD/DVD: Low data retrieval speed and limited storage capacity.
  • Tape Drive: High storage capacity and cost-effectiveness but slow data retrieval and limited accessibility.
The last four examples are considered ‘legacy media’ in 2023, but I have added them because they are still in use on legacy systems. There are surprisingly a lot of large capacity tape drives still in use because their storage capacity can still be larger than hard disks.


Secondary storage, by its definition of secondary storage, provides efficient data management, offering a budget-friendly and dependable solution for long-term data preservation. 

Although it may come with a slight trade-off regarding data retrieval speed, its advantages far surpass this minor limitation. From hard drives and SSDs to optical disks and cloud storage, the diverse types of secondary storage cater to various needs and purposes.

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