Data Management Glossary
Storage Tiering
What is Storage Tiering?
Storage Tiering refers to a technique of moving less frequently used data, also known as cold data, from higher performance storage such as SSD to cheaper levels of storage or tiers such as cloud or spinning disk.
The term “storage tiering” arose from moving data around different tiers or classes of storage within a storage system, but has expanded now to mean tiering or archiving data from a storage system to other clouds and storage systems.
Storage tiering is now considered a core feature of modern storage systems and recently has become part of default configuration for next generation storage like AWS FSx ONTAP. Block-level data storage solutions include: NetApp FabricPool and Dell PowerScale CloudPools.
Storage-agnostic data management and data tiering have emerged as more and more enterprise organizations adopt hybrid, multi-cloud, and edge IT infrastructure strategies. See also cloud tiering and choices for cloud data tiering.
Storage Tiering Cuts Costs Because 70%+ of Data is Cold
As data grows, data storage costs grow. It is easy to think the solution is more efficient storage. Or simply buy more storage. But data management is the real solation. Typically over 70% of data is cold and has not been accessed in months, yet it sits on expensive storage hardware or cloud infrastructure and consumes the same backup resources as hot data.
As a result, data storage costs are rising, backup times are slowing and disaster recovery (DR) is unreliable. The sheer bulk of this data makes it difficult to leverage newer options like Flash and Cloud.
Data Tiering Was Initially Used within a Storage Array
Data Tiering was initially a technique used by storage systems to reduce the cost of data storage by tiering cold data within the storage array to cheaper but less performant options. For example, moving data that has not been touched in a year or more from an expensive Flash tier to a low-cost SATA disk tier.
Typical storage tiers within a storage array or on-premises storage device include:
- Flash or SSD: A high-performance storage class but also very expensive. Flash is usually used on smaller data sets that are being actively used and require the highest performance.
- SATA Disks: High-capacity disks with lower performance that offer better price per GB vs SSD.
- Secondary Storage, often Object Storage: Usually a good choice for capacity storage – to store large volumes of cool data that is not as frequently accessed, at a much lower cost.
Increasingly, enterprise IT organization are looking at another option: tiering or archiving data to a public cloud.
- Public Cloud Storage: Public clouds currently have a mix of object and file storage options. The object storage classes such as Amazon S3 and Azure Blob (Azure Storage) provide tremendous cost efficiency and all the benefits of object storage without the headaches of setup and management.
- Cloud NAS has also become increasingly popular, but if unstructured data is not well managed, data storage costs will be prohibitive.
Cloud Storage Tiering is now Popular
Tiering and archiving less frequently used data or cold data to public cloud storage classes is now more popular. This is because customers can leverage the lower cost storage classes within the cloud to keep the cold data and promote them to the higher cost storage classes when needed.
For example, data can be archived or tiered from on-premises NAS to Amazon S3 Infrequent Access or Amazon Glacier for low ongoing costs. Later you can move it to Amazon EFS or FSX when you want to operate on it and need performance.
Cloud isn’t just low-cost data storage
The cloud offers more than low-cost data storage. Advanced security features such immutable storage can prevent ransomware. Cloud native services from analytics to machine learning can drive value from your unstructured data.
To take advantage of these capabilities and to ensure you’re not treating the cloud as just a cheap storage locker, tiered data must be accessible natively in the cloud without requiring third-party software. This requires the right approach to storage tiering, which is file-tiering, not block-tiering.
Block Tiering Creates Unnecessary Costs, Lock-In
Block-level storage tiering was first introduced as a technique within a storage array to drive efficiency by leveraging a mix of technologies such as more expensive SSD disks and cheaper SATA disks.
Block storage tiering breaks a file into various metadata blocks that contain information about the file, and data blocks that are chunks of the original file. Block-tiering moves less used cold blocks to lower, less expensive tiers, while hot blocks and metadata are typically retained in the higher, faster, and more expensive storage tiers.
Block tiering is a technique used within the storage operating system or filesystem and is proprietary. Storage vendors offer block tiering to reduce the cost of their storage environment. Many storage vendors are now expanding block tiering to move data to the public cloud or on-premises object storage.
Block storage tiering, often called CloudPools, such as NetApp FabricPool and Dell EMC Isilon CloudPools, is done inside the storage operating system as a proprietary solution. It has several limitations when it comes to efficiency of reuse and efficiency of storage savings.
- Firstly, with block tiering, the proprietary storage filesystem must be involved in all data access since it retains the metadata and has the “map” to putting the file together from the various blocks.
- This also means that the cold blocks that are moved to a lower tier or the cloud cannot be directly accessed from the new location without involving the proprietary filesystem. This is because the cloud does not have the metadata map and the other data blocks, file context and attributes to put the file together.
- So, block tiering is a proprietary approach that often results in unnecessary rehydration of the data.
With block storage tiering, the only way to access data in the cloud is to run the proprietary storage file system in the cloud which adds to costs. Also, many third-party applications such as backup software that operate at a file level require the cold blocks to be brought back or rehydrated. This defeats the purpose of tiering to a lower cost storage and erodes the potential savings.
For more details, read the white paper: Block vs. File-Level Tiering and Archiving.
Learn more about Komprise Data Tiering.
What is storage tiering and how does it work?
Storage tiering is the process of automatically moving data between storage tiers based on usage, age, performance needs, and cost. Frequently accessed “hot” data stays on fast premium storage, while inactive “cold” data is moved to lower-cost tiers such as object storage or cloud. This helps organizations balance performance and cost.
Why is storage tiering especially important now?
Storage tiering is increasingly important because enterprises are facing rising NAND flash prices, rapid unstructured data growth, tighter IT budgets, and growing AI infrastructure demands. The right approach to storage tiering helps preserve expensive high-performance storage for active workloads while reducing waste from inactive data. See Intelligent Tiering.
What is the difference between storage tiering and backup or archiving?
Storage tiering is designed to optimize active storage costs by relocating cold data while preserving transparent user access. Backup focuses on recovery copies, and archiving focuses on long-term retention. The Komprise Transparent Move Technology (TMT) approach to tiering complements both strategies by reducing the amount of expensive primary storage and backup footprint required.
How does Komprise improve storage tiering?
Komprise provides storage-agnostic intelligent data tiering across NAS, object, and cloud environments. Unlike vendor-native tools tied to one platform, Komprise analyzes file usage across heterogeneous storage, moves cold data transparently, preserves file access, and helps customers avoid vendor lock-in.
What is Komprise Flash Stretch and how does it relate to storage tiering?
Komprise Flash Stretch is an assessment and optimization approach that helps organizations reclaim expensive flash capacity by identifying inactive file data suitable for tiering. By moving cold data to lower-cost storage, organizations can extend existing flash investments, delay upgrades, and reduce capital spending.
Can storage tiering help AI initiatives?
Yes. Storage tiering frees premium storage capacity for GPU, analytics, and AI workloads while helping organizations identify valuable unstructured data that can be used for AI training, retrieval, and RAG pipelines.