Data Management Glossary
Secondary Storage
What is Secondary Storage?
Secondary storage devices are storage devices that operate alongside the computer’s primary storage, RAM, and cache memory. Secondary storage is for any amount of data, from a few megabytes to petabytes. These devices store almost all types of programs and applications. This can consist of items like the operating system, device drivers, applications, and user data. For example, internal secondary storage devices include the hard disk drive, the tape disk drive, and compact disk drive.
Some key facts about secondary storage:
- It is typically designed for long-term storage – its non-volatile media such as solid state devices, optical or magnetic storage devices such as tape.
- It is typically orders of magnitude cheaper than primary storage – it is designed for more capacity storage than performance.
- It can either be hosted on-premises at data centers or in the cloud.
- It can use file (Network Attached Storage NAS via NFS and SMB/CIFS protocols) or block-based storage-area-network (SAN) or object formats. Object-based secondary storage is extremely popular today especially in the cloud.
- Examples include: Amazon Simple Storage Service (S3), Amazon Glacier, Azure Blob, Google Cloud ColdLine Storage, and on-premises object stores such as IBM Cloud Object Storage.
- Use cases include: Cold data storage, Cold data tiering or data archiving, data backup and Disaster Recovery storage.
- Komprise data management software is used to find the right data to place on secondary storage and move data to secondary storage without user disruption.
Secondary Storage Data Tiering
Secondary storage typically tiers or archives inactive cold data and backs up primary storage through data replication or other data backup methods. This replication or data backup process, ensures there is a second copy of the data. In an enterprise environment, the storage of secondary data can be in the form of a network-attached storage (NAS) box, storage-area network (SAN), or tape. In addition, to lessen the demand on primary storage, object storage devices may also be used for secondary storage. The growth of organizational unstructured data has prompted storage managers to move data to lower tiers of storage, increasingly cloud data storage, to reduce the impact on primary storage systems. Furthermore, in moving data from more expensive primary storage to less expensive tiers of storage, knowns as cloud tiering, storage managers are able to save money. This keeps the data easily accessible in order to satisfy both business and compliance requirements.
When data tiering and archiving cold data to secondary storage, it is important that the archiving / tiering solution does not disrupt users by requiring them to rewrite applications to find the data on the secondary storage. Transparent archiving is key to ensuring that data moved to secondary storage still appears to reside on the primary storage and continues to be accessed from the primary storage without any changes to users or applications. Transparent move technology solutions use file-level tiering to accomplish this.
Learn More: Why Komprise is the Easy, Fast, No Lock-In Path to the Cloud for file and object data.
Secondary Storage FAQs
Why is the cost gap between primary and secondary storage more important than ever in 2026?
Gartner is calling it Memflation. NAND flash prices are forecast to surge 234% in 2026 driven by AI data center demand consuming available supply, with no meaningful pricing relief expected until late 2027. This makes the cost gap between primary flash-based storage and lower-cost secondary storage wider than at any point in recent memory. For enterprises storing 60-70% of their NAS data as cold, inactive files that have not been accessed in over 90 days, the decision to keep that data on expensive primary storage is now costing significantly more per gigabyte than it did 12 months ago.
Intelligently moving cold unstructured data to secondary storage through automated tiering is the most direct response available. Komprise Intelligent Tiering identifies cold data automatically based on last accessed time and other data attributes, then moves it to lower-cost cloud or object storage destinations via patented Transparent Move Technology. Data is moved in native format, users access it transparently from its original path via Dynamic Links, and no rehydration is required. The Komprise Flash Stretch Assessment quantifies exactly how much capacity can be reclaimed and at what savings before any action is taken.
How does secondary storage support AI data preparation for unstructured data?
Secondary storage plays a dual role in enterprise AI programs. On one side it is where most historical unstructured data ends up, making it a rich source of training data, reference material, and domain-specific context for AI models and RAG pipelines. On the other side, without proper metadata and governance, data on secondary storage is effectively invisible to AI systems. Files stored on object storage with no enriched metadata, no classification, and no unified index are just bytes. AI pipelines cannot find them, filter them, or trust them.
Komprise bridges this gap by ensuring that data tiered to secondary storage remains a first-class citizen in the enterprise data estate. The Global Metadatabase indexes all file and object data regardless of which storage tier it occupies, so data on secondary storage is searchable by metadata and custom tag criteria alongside data still on primary storage. KAPPA data services can extract domain-specific metadata from file content at any tier, enriching the Global Metadatabase with business context that makes secondary storage data usable by AI pipelines without needing to be recalled to primary storage first. Komprise Smart Data Workflows can then curate and deliver governed datasets from any storage tier directly to AI platforms in native format, making secondary storage an active AI data asset rather than a passive archive.
How does Komprise help enterprises decide what belongs on primary versus secondary storage?
The boundary between primary and secondary storage is rarely managed systematically in most enterprise environments. Data accumulates on primary NAS by default as new files are created, and without an automated lifecycle management system, cold data stays on primary storage indefinitely alongside active working files. Over time, primary storage becomes a mix of hot data that needs fast access and cold data that has not been touched in years, making it impossible to optimize costs without manual audits that do not scale beyond terabytes.
Komprise addresses this through continuous, analytics-driven data placement. Komprise scans the entire unstructured data estate and builds a complete picture of what data exists, how old it is, who owns it, when it was last accessed, and how fast different parts of the environment are growing. Tiering policies are typically based on last accessed time, moving data that has not been accessed within a defined threshold to lower-cost secondary storage automatically. For more precise placement decisions, Deep Analytics Actions allows a saved query to serve as the input to a tiering policy, enabling IT teams to identify specific datasets for secondary storage based on any combination of metadata and custom tag criteria. The result is a primary storage environment optimized for active workloads and AI initiatives, with cold data continuously and automatically right-placed to secondary storage at a fraction of the cost.
What is Secondary Storage?
Secondary storage, sometimes called auxiliary storage, is non-volatile and is used to store data and programs for later retrieval. It is also known as a backup storage device, tier 2 storage, external memory, secondary memory or external storage. It is a non-volatile device that holds data until it is deleted or overwritten.
Secondary Storage Devices
Here are some examples of secondary storage devices:
- Hard drive
- Solid-state drive
- USB thumb drive
- SD card
- CD
- DVD
- Floppy Diskette
- Tape Drive
What is the difference between Primary and Secondary Storage?
Primary storage is the main memory where the operating system resides and is likely to be temporary, more expensive, smaller and faster and is used for data that needs to be frequently accessed.
Secondary storage can be hosted on premises, in an external device, or in the cloud. It is more likely to be permanent, cheaper, larger and slower and is typically used for long term storage for cold data.