Linux服務器上經常遇到一些系統和應用上的問題，如何分析排查，需要利器，下面總結列表了一些常用工具、trace tool；最后也列舉了最近hadoop社區在開發發展的分布式系統的trace tool。

概覽：
http://www.brendangregg.com/index.html
http://www.slideshare.net/brendangregg/linux-performance-analysis-and-tools
https://github.com/brendangregg/perf-tools/
http://www.brendangregg.com/linuxperf.html
引用linux-performance-analysis-and-tools中圖片，說明這些tool試用層次位置
其中提到了的工具，大部分在我日常工具箱里或者在實踐的案例里面使用過, 都有很高的價值，這里方便大家索引下：

• nicstat: 參見 這里

• oprofile: 參見 這里

• perf: 參見 這里

• systemtap: 參見 這里

• iotop: 參見 這里

• blktrace: 參見 這里

• dstat: 參見 這里

• strace: 參見 這里

• pidstat: 參見 這里

• vmstat: 參見 這里

• slabtop: 參見 這里

• tcpdump: 參見 這里

• free: 參見 這里

• mpstat: 參見 這里

• netstat: 參見 這里

• tcprstat: 參見 這里

• uname -a 或 cat /proc/version #print system information

• Linux hadoopst2.cm6 2.6.18-164.el5 #1 SMP Tue Aug 18 15:51:48 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

• uptime

• 15:42:46 up 674 days, 6 min, 35 users, load average: 1.30, 5.97, 11.53

• cat /etc/redhat-release

• Red Hat Enterprise Linux Server release 5.4 (Tikanga)

• lsb_release

• LSB Version:  :core-3.1-amd64:core-3.1-ia32:core-3.1-noarch:graphics-3.1-amd64:graphics-3.1-ia32:graphics-3.1-noarch

• cat /proc/cpuinfo

• cat /proc/meminfo

• lspci - list all PCI devices

• lsusb - list USB devices

• last, lastb - show listing of last logged in users

• lsmod — show the status of modules in the Linux Kernel

• modprobe - add and remove modules from the Linux Kernel

• ps

• To print a process tree: ps -ejH / ps axjf

• To get info about threads: ps -eLf / ps axms

• ulimit -a

• lsof - list open files, UNIX一切皆文件

• lsof -p PID

• rpm/yum

• rpm -qf FILE #文件所屬rpm包

• rpm -ql RPM #rpm包含文件

• /var/log/yum.log #yum 更新包日志

• /etc/XXX #系統級程序配置目錄， 如

• /etc/yum.repos.d/ yum源配置

• /var/log/XXX #日志目錄， 如

• /var/log/cron #crontab日志，可以查看調度執行情況

• ntpd - Network Time Protocol (NTP) daemon，同步集群中機器時間

• squid - proxy caching server，集群WebUI的代理

• mpstat - Report processors related statistics. 注意%sys %iowait值

• vmstat - Report virtual memory statistics

• iostat - Report Central Processing Unit (CPU) statistics and input/output statistics for devices and partitions.

• netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

• netstat -atpn | grep PID

• ganglia - a scalable distributed monitoring system for high-performance computing systems such as clusters and Grids.

• sar/tsar - Collect, report, or save system activity information; tsar是淘寶自己改進的版本

• 定時采樣（每分鐘），可查歷史記錄（默認5分鐘），可彌補ganglia顯示更詳細信息

• iftop - the "top" bandwidth consumers shown. iftop wiki

• iotop

• vmtouch, Portable file system cache diagnostics and control

• telnet/nc IP PORT - 確認目標端口是否可訪問，只ping通不一定端口可訪問，可能防火墻等禁止

• ifconfig/ifup/ifdown - configure a network interface

• traceroute - print the route packets trace to network host

• nslookup - query Internet name servers interactively

• tcpdump - dump traffic on a network， 類似開源工具 wireshark, netsniff-ng, 更多工具比較

• lynx - a general purpose distributed information browser for the World Wide Web

• tcpcp - allows cooperating applications to pass ownership of TCP connection endpoints from one Linux host to another one.

• ldconfig - configure dynamic linker run time bindings

• ldconfig -p | grep SO 查看so是否在link cache中

• ldd - print shared library dependencies， 查看exe或so依賴的so

• nm - list symbols from object files，可grep查找是否存在相關的symbol，是否Undefined.

• readelf - Displays information about ELF files. 可現實elf相關信息，如32/64位，適用的OS，處理器

• gdb

• cat /proc/$PID/[cmdline|environ|limits|status|...] - 進程相關信息

• pstack - print a stack trace of a running process

• pmap - report memory map of a process

• JDK Tools and Utilities

• Java Troubleshooting Tools

• jinfo - print java process information, 如classpath，java.libary.path（jni so目錄）

• jstack - print a stack trace of a running java process，可查看死鎖情況

• jmap - report memory map of a java process

• jmap -histo:live 可觸發full gc

• jmap -dump:live,file=$FILE 可dump heap內存，用于jhat等工具debug分析object在heap的占用情況

• jhat - Heap Dump Browser - Starts a web server on a heap dump file (eg, produced by jmap -dump), allowing the heap to be browsed.

• 起http服務，瀏覽器訪問查看

• -J-mxXXXm ，分析大文件時需要加大heap大小

• 若有對象數據超大或內存占用過多，極有可能memory leak

• Memory Analyzer (MAT) - eclipse plugin，Java heap analyzer

• 可視化工具，但受到機器內存的限制，無法分析太大的heap dump file

• jdb - 可起服務做server，eclipse等工具遠程連接調試

• jstat - Java Virtual Machine Statistics Monitoring Tool

• jstatd - Virtual Machine jstat Daemon，可配合jvisualvm

• jvisualvm - Java Virtual Machine Monitoring, Troubleshooting, and Profiling Tool；可遠程連接jstatd/jmx, 可視化展示工具：演示

• jvmtop - In a top-like manner, displays JVM internal metrics (e.g. memory information) of running java processes.

• JVM performance optimization JVM開發者寫的優化文章

1. Overview

1. Compilers

1. Garbage collection

1. Concurrently compacting GC

1. Scalability

• HPROF - Heap Profiler： java -agentlib:hprof

• 寫log，但系統在線或無法源碼時

• strace - trace system calls and signals

• 示例：strace/ltrace的應用實例

• 示例：可跟蹤系統調用時間，如機器cpu:%sys高的問題

• blktrace, generate traces of the i/o traffic on block devices

• ltrace - A library call tracer

• xtrace

• gprof - a performance analysis tool, sampling and call-graph profiling

• valgrind - an instrumentation framework for building dynamic analysis tools. automatically detect many memory management and threading bugs, and profile your programs in detail

• systemtap - a simple command line interface and scripting language for writing instrumentation for a live running kernel plus user-space applications for complex tasks that may require live analysis, programmable on-line response, and whole-system symbolic access.

• Linux版DTrace（SUN在Solaris上開發的）

• 功能強大，kernel， user-space app，cross language（java perl python ruby），build-in markers（pg mysql）

• can write and reuse simple scripts to deeply examine the activities of a live system

• Data can be extracted, filtered, and summarized quickly and safely, to enable diagnoses of complex performance or functional problems

• 豐富的 "tapset" script library

• btrace - dynamic tracing tool for the Java platform. UserGuide

• 基于動態字節碼修改技術(Hotswap)來實現運行時java程序的跟蹤和替換, 實現原理

• BTrace使用總結

• 詳細介紹

• byteman - simplifies tracing and testing of Java programs. Can modify a running application without needing to stop and restart it.

• define rules specifying the side effects you want to inject 而 BTrace類java語法

• Dapper, a Large-Scale Distributed Systems Tracing Infrastructure

• x-trace, a network diagnostic tool designed to provide users and network operators with better visibility into increasingly complex Internet applications.

• HTrace， a tracing framework intended for use with distributed systems written in java

• Add Tracing to HDFS

• Update HTrace for HBase