As data grows, more storage and processing power is needed to scale up and out to meet the demands and complexities of enterprise information management systems. Although data grows unbounded, IT budgets are limited. Therefore, business owners must come up with a data management strategy that both satisfies user requirements for data accessibility and performance, and observes cost constraints.
Fortunately, the value of data tends to change over time. Aged data becomes less interesting and is less frequently accessed, and the largest percentage of active reporting and analytics takes place against the most current operational data available. Managing and storing older data in a cost-effective manner is key for organizations seeking to decouple their data growth from expensive hardware growth.
SAP offers users several technology options, based on cost, scale, and data volume, for managing and accessing each temperature tier of data.
Hot and Cold Data Tiering Options
Hot data is stored in-memory within SAP HANA. Non-volatile memory—known as SAP HANA persistent memory (PMEM)—has a lower TCO and is larger than the classic DRAM (dynamic random-access memory), can be added to SAP HANA to expand overall memory capacity and increase the volume of hot data that can be stored in-memory. Data in PMEM maintains its state after system shutdown, which translates to improved database startup time since data does not need to be loaded into memory from disk.
Cold data is primarily stored on the lowest cost storage tiers but remains accessible to SAP HANA via SQL on request. The cold data tier for native SAP HANA applications and SAP Business Warehouse (SAP BW) applications is managed by SAP Data Hub or the SAP HANA Spark Controller, for data storage in Data Hub or Hadoop, respectively. Customers using SAP BW also have the BW NLS (near-line storage) option to store cold data in an external repository such as SAP IQ.
Warm Data Tiering Options
Let’s turn to the technology options for warm data.
The first option, Paged Attributes, is an alternative that is only applicable to SAP S/4HANA and SAP Business Suite powered by SAP HANA. Paged Attributes allows table columns to be loaded page by page from the HANA persistence layer into memory as needed, without requiring the entire table to be loaded into memory at the same time. Paged Attributes are preferably unloaded from HANA memory to disk based on a least recently used algorithm. Find out more about Paged Attributes.
SAP HANA dynamic tiering is an optional add-on to the SAP HANA database for managing less frequently accessed warm data. It extends SAP HANA memory by providing the ability to create, query, and load data into disk-based, columnar database tables—called extended tables and multistore tables. While easy to implement and manage, along with good scalability to 100TB of compressed data, SAP HANA dynamic tiering supports only SAP HANA native applications. The SAP HANA dynamic tiering server may be deployed on commodity hardware, making it a lower cost option for managing warm data, although with slower performance and reduced functional parity compared to HANA in-memory nodes.
An Extension Node is a dedicated HANA in-memory node for warm data processing that allows the SAP HANA database system to scale out at a lower cost and is appropriate for both SAP BW and native SAP HANA applications. It is, at its core, an additional SAP HANA node with relaxed memory and CPU requirements but with the same functionality as a pure SAP HANA node.
An Extension Node keeps most of its data primarily in the disk-backed persistence layer and loads data into memory only when needed. When a query is executed to access warm data on an extension node, that data is pulled from disk into memory and operates like a normal SAP HANA worker node for processing. If memory is scarce, the Extension Node unloads other data from memory to disk based on a least recently used algorithm. Because the data can reside, for the most part, on disk, an Extension Node can manage up to four times the volume of data as a regular SAP HANA worker node. With a requirement for certified SAP HANA hardware, Extension Nodes are the highest cost but best performing option for warm data management.
Data Tiering: A Trusted Approach for the Intelligent Enterprise
Today’s challenges of balancing and managing rapidly growing data volumes—as businesses continue to accumulate information required to control their daily and strategic operations—are made manageable with the data tiering options from SAP. Organizations can implement a data lifecycle management strategy, that moves data to the storage and processing tier with the cost and performance characteristics best suited for that data. Data tiering options from SAP provide a trusted approach for intelligent enterprises to manage data growth effectively and economically.
Stay tuned as we provide a deeper-dive into SAP HANA data tiering options over the coming months.