Benchmark
Introduction blktrace is block layer IO tracing mechanism while provides detailed information about request queue operations up to user space Install on RedHat/CentOS/OEL Download epel-release-6-8.noarch.rpm and install then using below command. #yum install blktrace Setup #mount -t debugfs debugfs /sys/kernel/debug Add an entry into
Server
http://lnav.readthedocs.org/en/latest/index.html Command Reference This reference covers the commands used to control lnav. Consult the built-in help in lnav for a more detailed explanation of each command. Note that almost all commands support TAB-completion for their arguments, so if you are in doubt as
Tool
问题引入——处理数据时候想要做除法计算，发现直接用$A/$B是行不通的，后来才发现linux做数学运算，需要调用bc命令，查了以下其用法，简单记录如下 一、四则运算，取余，乘方。 加 + 减 – 乘 * 除 / 取余 % 乘方 ^ 调用格式，现在为止发现有两种调用格式可用： 1、 ################################ a=`bc -l << END scale=30 5/4 END` ################################ b=`echo 'scale=30;5/4'%7