Is the server processing capability correct?

Is the server processing capability correct?

Author: Cheng Xiaoxu

 

1 [question]

Anyone who has written a technical solution knows that when the technical solution is finally implemented to the project implementation and deployment, IT equipment and environment to be deployed for the current solution must be prepared, including: required network environment, port, bandwidth, networking mode, and network security assurance measures; performance and quantity of server devices to be configured; storage devices, capacities, and storage rates to be configured; you even need to consider the backup device capacity, backup I/O count, speed, and backup policy of the entire system.

Strictly speaking, whether it is a system manufacturer, an integrated company, a research institute, or a design company, when the hardware configuration of the solution is finally provided, the customer's business development trend and system redundancy should be properly taken into consideration based on business needs. Detailed estimates include the network bandwidth, processing capability, and data storage capacity indicators of the current business needs. Therefore, based on your project cases and experience, this article briefly describes how to properly estimate computer processing capabilities for your reference.

2 [performance evaluation criteria]

As we all know, the TPC-C standard of the Transaction Processing Performance Committee is the industry standard for measuring and measuring the performance of computer hardware equipment. With the popularity of the B/S technical architecture, the spec organization has specifically released a performance measurement standard for the Web server to respond to client web access requests, that is, the spec web series. Therefore, if it is a traditional server based on the transaction processing mode, still using the TPC-C method for calculation; if it is a Web server, it needs to use spec web series standards for calculation. However, it is a pity that many people ignore these two differences when measuring server performance.

1.1 TPC-C standards

The TPC-C benchmark is a performance benchmark established by the transaction processing board dedicated to demonstrating online transaction processing performance (OLTP, it is measured to enable customers to evaluate the performance of different online transaction processing systems that run in a standard database in a controllable state.

The transaction processing of the TPC-C is implemented on a database of 9 tables, including: Update, insert, delete, terminate, and access to the primary and secondary keys, 95% of the response time for each transaction should be less than or equal to 5 seconds, and the inventory level response time can be less than 60 seconds. The TPC-C value represents the amount of standard transactions processed per minute, measured in tpmc.

1.2 spec web standards

Spec web99, the number of concurrent accesses that the Web server can support. The specweb99 detection program simulates a customer's slow Internet connection and sends an HTTP workload request to the web server.

Spec web2005, as the successor of specweb99, continues the traditional spec testing principle. It sends an http get request to the server through multiple clients and requests to call webpage files on the web server, these files range from several kilobytes to several megabytes. In the same time, the more requests the server answers, the higher the server's processing capability on the client, the better the system's Web performance.

3 [Performance Estimation Formula] 3.1 Common Error Estimation Methods

During the review of technical solutions and bidding and evaluation, I often see the following table to evaluate the server processing capability:

Example 1:

Example 2:

I don't know where this evaluation method started. In the technical solution documentation, I have seen such an evaluation model and table for many times. That is, it is not the evaluation method of TPC-C, not the evaluation method of spec web system.

3.2 TPC-C Estimation Formula

TPC-C is to measure the number of standard transactions that can be processed by computer equipment per minute. Therefore, to estimate the demand for processing capability in an application scenario, in essence, it is to estimate the standard TPC-C transaction volume corresponding to each type of business processing transactions, and then consider the redundant volume as appropriate. The TPC-C calculates the number of transactions per minute, measured in tpmc.

The general estimation formula of TPC-C is as follows:

TPC-C = Σ (Business Transaction volume per minute * standard transaction volume ratio)/(1-redundancy rate ).

For example, a business system has two types of business transaction operations, with 30000 business transactions per minute. Each business transaction 1 operation is equivalent to 0.5 standard TPC-C transactions; transaction 2: 20000 transactions per minute. Each business transaction 2 is equivalent to two standard TPC-C transactions. 30% of system redundancy is considered. The processing capability required by the business application is:

Server processing capability (tpmc) = (30000x0.5) + (20000X2)/(1-30%) = 78581.

3.3 spec web Estimation Formula

The spec web2005 standard measures the maximum number of Web requests that a Web server can effectively respond to clients. Therefore, the calculation result should be a Web request number in units.

When evaluating the spec web2005 value of the application server, the common method is to estimate the number of concurrent users based on the system's online users and their on-line rate, estimate the number of HTTP requests that may be initiated in daily business scenarios.

Spec web2005ReferenceThe estimation formula is as follows: (Note: The formula is for reference only and you need to design an estimation model based on the specific conditions of the project)

Web Access response capability (SPEC web2005) = (number of online users * online rate * Average number of HTTP requests initiated by online users)/(1-redundancy rate ).

For example, if the number of online users in a business system is 2000, the on-line rate is 10%, and the average number of HTTP requests initiated by each online user is 3, 30% of system response capability redundancy is considered. The Web Server responsible for the service request has the following response capabilities:

Web Access response capability (count) = 2000 * 10% * 3/(1-30%) = 857.

4. Application Instance]

The following uses the performance estimation of an Application Server (Web Service middleware deployed) in an actual project as an example.

The middleware product runs on the application server, undertakes various business logic components of the system to run computing, converges system users' access requests to the database server, and centrally provides external application services. Through analysis, the application server performance needs to provide web application services and business logic processing.

In terms of Web application services, based on the business forecast data, the average number of online concurrent users on the application server is estimated to be 120, and the concurrent online rate is 20%. Each user initiates an average of three HTTP links, considering the 30% system response redundancy capability, according to The specweb99 evaluation standard, Web Application Service Performance Requirements: Maximum number of concurrent connections of web servers = (120 × 20% × 3)/(1-30%) = 103.

In terms of business logic processing performance, the main application service component performance requirements are: group data monitoring and analysis, provincial data monitoring and analysis, and business data query. According to the survey statistics, the group's data is 3585 per minute, the province's data is 51667 per minute, and the Business Information Query request is 2151 per minute on average, each business operation requires three standard tpcc transactions, namely, provincial data monitoring and analysis. Each business operation requires two tpcc transactions and business information queries. Each business operation requires about two tpcc transactions; the tpcc value is calculated as follows:

Therefore, the processing capability configuration of the application server cannot be lower 196731 tpmcIts web2005 configuration indicators cannot be lower 103.

5. Experience Summary]

First,For the transaction processing application scenario, we need to use the TPC-C estimation method to estimate the total tpmc value. For the Web Client Request Response Application Scenario, in addition to estimating the service processing capability, you also need to evaluate the Web request response capability of the client. The actual server configuration is generally not lower than the estimation result.

Second,In addition to the processing capability required for storing business processing, you also need to consider other basic service running overhead in the device running environment, such as the operating system, database server, Web server, and Application Middleware.

Third,Due to the rapid development of hardware equipment in the current period, the tpcc value of standard PC servers is usually several hundred thousand, with a high configuration or even millions. Therefore, we also have two experiences to remind you:

FirstIf the tpcc value of the business needs is calculated to be very low (most applications), configuring a low-end PC server can meet the processing capability requirements, the tpcc value cannot be compiled randomly because the customer wants to provide a high-configuration device; instead, the customer should look for more powerful reasons from other aspects.

SecondDue to the enhancement of the processing capability of PC servers, the tpcc value is often no longer a good reason to select minicomputers. However, when the customer needs to provide a minicomputer solution, you can try to find a solution in terms of stability, reliability, high I/O requirements, device homogeneous requirements, and special requirements of peripheral devices. Instead, you cannot simply consider the tpcc value.