Hitachi 9900 manual Unmatched Performance and Scalability, Truly Scalable Performance

Unmatched Performance and Scalability

Truly Scalable Performance

Based on the internal switched Hi-Star™architecture, the Hitachi Freedom Storage™ Lightning 9900™ V Series shows unmatched performance scalability. This chapter discusses the ability to dramatically add more online transaction processing (OLTP) users and mixed decision-support and OLTP workloads without a user response time decrease. The more capacity and connectivity added to a Lightning 9900 V Series system, the more total the bandwidth increases. As Table 4 shows, total aggregate bandwidth is ten times that of competition.

When new application workloads are added to a Lightning 9980V™ system with an existing workload, neither the new nor the existing workloads suffer performance degradations from the sharing of internal resources and bandwidth. The following series of tests proves this point. By measuring user-response time while workloads are added to the system, we can illustrate this phenomenon.

Model	Control	Data	Aggregate	User-useable
Type	Bandwidth	Bandwidth	Bandwidth	Throughput
Lightning 9970V™ system	2.6GB/sec	5.3GB/sec	7.9GB/sec	5.3GB/sec
Single Cabinet
Lightning 9980V™ system	5.3GB/sec	10.6GB/sec	15.9GB/sec	10.6GB/sec
Multi-Cabinet
Competition	1.6GB/sec	1.6GB/sec	1.6GB/sec	1.6GB/sec

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The more capacity and connectivity added to a Lightning 9900 V Series system, the more total internal bandwidth increases.

Table 4 – Lightning 9980V system bandwidth is ten times that of competition.

Internal Switching Overcomes the Limitations of Shared-bus Architectures

It can be seen from Figure 24 that very little user-response time reduction occurs in the OLTP performance of the Lightning 9980V system. This is because the Lightning 9900 V Series system, with its Hi-Star architecture, essentially has its own internally routed path for each workload. This means that the main reason for performance decline of a competitive shared-bus architecture, i.e. bus contention, does not occur with Lightning 9900 V Series systems. Although there may be some contention in cache, many simultaneous operations concurrently happen at the cache, so it far exceeds the demands of most applications.

There Is NO Match for the Performance of the Lightning 9980V System

As shown in Figure 23, during the first 30 minutes of the test 1800 simulated users were connected to the first OLTP server, and the transactions per minute (TPM) rate and user-response time reached steady state at about 2200TPM and 3.0 seconds respectively. OLTP user response time is the delay time between when a simulated user issues a transaction request and when the request responds with a commit. After 30 minutes, a second OLTP server was connected with an additional 1800 simulated users, bringing the total number of users to 3600.

After one hour, the first decision support system (DSS) workload was started. The DSS workload began a series of full table scans, counting records from a 1.2 billion row table. The transfer rate for the DSS system was 380MB/sec or 3.4 million rows per second. We

Bottleneck-free performance with the Lightning 9900 V Series.

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