The SPC Benchmark-2 (SPC-2) is a series of related benchmark performance tests that simulate the sequential component of demands placed upon on-line, non-volatile storage in server class computer systems. SPC-2 provides measurements in support of real world environments characterized by:

• Large numbers of concurrent sequential transfers.
• Demanding data rate requirements, including requirements for real time processing.
• Diverse application techniques for sequential processing.
• Substantial storage capacity requirements.
• Data persistence requirements to ensure preservation of data without corruption or loss.

SPC-2 is designed as a source of comparative storage subsystem performance information. It is intended to provide value throughout the storage product lifecycle (e.g. development of product requirements; product implementation; performance tuning; capacity planning;market positioning; and purchase evaluations).

In view of the broad applicability of the SPC-2 benchmark, it is anticipated that readers may wish to approach the present document via a variety of starting points.

SPC-2 is comprised of a set of I/O operations designed to demonstrate the performance of a storage subsystem when running business critical applications that require the large-scale, sequential movement of data. SPC-2 represents a segment of applications characterized predominately by large I/O’s, organized into one or more concurrent sequential patterns. Frequently encountered examples of such applications include:

1. Large file processing: applications, in a wide range of fields, which require simple sequential processing of one or more large files. Specific examples include scientific computing and large-scale financial processing.
2. Large database queries: scans or joins of large relational tables, such as those performed for data mining or business intelligence.
3. Video on demand: individualized video entertainment provided to a community of subscribers, by drawing from a digital film library.

High-Level workload model
Each of the three categories of sequential workload just enumerated is considered to represent a widespread class of storage applications in itself, and also to be a useful indicator of sequential performance. Each of these three categories of sequential work also exhibits a distinctive set of sequential processing techniques being applied at the application level. SPC2 therefore incorporates tests representative of all three of the identified categories of sequential work. Taking into account variations within the categories, SPC-2 incorporates a total of 19 individual tested workloads.

Tests of each workload are structured in a common way. Each workload defines a sequentially organized pattern of I/O requests, referred to as a Stream, which transfers a contiguous range of data (for example, a Stream might correspond to the reads or writes needed to transfer a specific file or to scan a specific table in a relational database). During SPC-2 test execution, the number of concurrent Streams of the defined type is varied, so as to observe the resulting range of data rates in megabytes per second. At least three different numbers of concurrent Streams are tested for each workload (a single stream, a maximum number of streams selected by the test sponsor, and an intermediate number of streams selected by the test sponsor). At the test sponsor’s discretion, additional intermediate numbers of streams can be added to the test sequence.

The storage made available to the benchmark driver for use in running the SPC-2 benchmark is referred to as the Application Storage Unit (ASU). The ASU represents an abstraction of storage media and does not require a particular physical implementation. The physical implementation is determined by the Test Sponsor.

The original SPC-1 benchmark has been characterised thus: "The SPC-1 storage benchmark is a major industry contribution for providers and buyers of storage networking technology. It is characterised predominantly as a random access environment for server-class computer systems and is modelled on the most ubiquitous applications in the market today – web servers, database servers and email servers."

SPC-2 benchmark result from IBM
IBM's SAN Volume Controller and its DS8300 disk sub-system, have achieved top scores for performance on the Storage Performance Council’s newly-released industry storage benchmark, SPC-2. The SPC-2 benchmark consists of three application-oriented sequential I/O performance tests, which include large file processing, large database queries and video on demand.

The IBM TotalStorage SAN Volume Controller demonstrated the best sequential throughput producing an average of 3,517 SPC-2 MBPS (megabytes per second). Additionally the IBM TotalStorage DS8300 followed closely behind, garnering the number two overall score in the test with a submitted result of 3,217 SPC-2 MBPS. The DS8300 was the top performer among tested enterprise disk storage subsystems.

The IBM TotalStorage SAN Volume Controller was launched more than two years ago and has been installed in more than 1,500 businesses worldwide.

The DS8000 series products feature three IBM Research-developed software innovations in caching that are designed to work together to deliver dramatically greater throughput and faster response times for a wide range of real-life workloads. A new prefetching feature preloads and manages sequential data in the cache so it always contains the needed data. This prefetching feature also enhances the previously announced Adaptive Replacement Cache technology that integrates and balances both of the critical caching and prefetching functions. The third innovation is designed to eliminate undesirable interactions between the read- and write-cache management while still allowing both caches to beneficially share memory resources.

Walter E. Baker, Administrator and Auditor for the Storage Performance Council, said: “The new SPC-2 benchmark provides an additional view of storage performance for customers seeking to assess performance based upon objective, verified benchmark results. A combination of SPC-1 and SPC-2 results provides a comprehensive view of the random and sequential I/O performance of storage products such as IBM’s SAN Volume Controller and DS8300.”