Some notes on the pressure measurement

1. First, we need to determine the basic environment of the pressure measurement, mainly server, network, disk.

Server CPU frequency and cache size has a large impact on the speed of program execution, in general, the impact of IO-intensive operations cache more, CPU-intensive operation of the main frequency impact more; Server CPU cores have a large impact on multithreaded programs, and for high-level languages, due to the number of CPU cores that can be obtained, This piece does not have a special configuration. However, for some languages such as plsql, it is important to determine the number of cores of the CPU to determine the thread of execution. As the current access to the program for the use of memory are more important, there is no memory for the performance of the large impact of the situation;

Network mainly determines the bandwidth, cross-network segment (room) need to determine the network equipment on each link (such as firewall) load capacity;

Disks can use IOPS as an evaluation standard, mechanical hard drives, solid state drives, shared storage, distributed storage, and different storage scenarios with very large bandwidth differences.

The ability to determine networks and disks can be used to roughly determine bandwidth by copying files between different machines.

2. Pressure measurement monitoring (Linux system)

In general, the main content that needs to be monitored is CPU, memory, IO, so the common command is Top,iostat, Vmstat

A. The top command can focus on the CPU, memory situation, note that the overall CPU utilization is low, does not mean that the application process CPU is not busy, but also need to look at a particular process CPU execution situation.

Memory consumption can be judged as follows:

mem:3925908k Total, 3787840k used, 138068k free, 12716k buffers

swap:4063224k Total, 2030264k used, 2032960k free, 596756k cached

In case of memory problems: Free + buffers + cached is a small or swap free combination.

b iostat command to determine the occupation of Io, such as Iostat-x-M 5, the command introduced a lot of articles;

C Vmstat command can determine whether there are process blocking, which is very useful for the judgment of multithreaded program execution;

Some notes on the pressure measurement