线上问题处理整理总结

来源：互联网发布：莱昂纳德14总决赛数据编辑：程序博客网时间：2024/05/17 06:56

1.处理磁盘空间满的问题，查找大于某个上限的文件

find / -xdev -size+500M -exec ls -l {} \;

2.避免停机，立即释放空间的示例 echo "">catalina.out

3.查看磁盘空间文件大小按照大小进行排序：du -sh /usr | sort -nr

--内存OOM问题处理的命令

假设pid为6055

jmap -heap 6055

[root@SZB-L0032773 ~]# jmap -heap 6055
Attaching to process ID 6055, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.91-b14

using parallel threads in the new generation.
using thread-local object allocation.
Concurrent Mark-Sweep GC

Heap Configuration:
   MinHeapFreeRatio         = 40
   MaxHeapFreeRatio         = 70
   MaxHeapSize              = 1048576000 (1000.0MB)
   NewSize                  = 174456832 (166.375MB)
   MaxNewSize               = 174456832 (166.375MB)
   OldSize                  = 874119168 (833.625MB)
   NewRatio                 = 2
   SurvivorRatio            = 8
   MetaspaceSize            = 21807104 (20.796875MB)
   CompressedClassSpaceSize = 1073741824 (1024.0MB)
   MaxMetaspaceSize         = 17592186044415 MB
   G1HeapRegionSize         = 0 (0.0MB)

Heap Usage:
New Generation (Eden + 1 Survivor Space):
   capacity = 157024256 (149.75MB)
   used     = 124465352 (118.69940948486328MB)
   free     = 32558904 (31.05059051513672MB)
   79.26504807002556% used
Eden Space:
   capacity = 139591680 (133.125MB)
   used     = 124287480 (118.52977752685547MB)
   free     = 15304200 (14.595222473144531MB)
   89.03645260233274% used
From Space:
   capacity = 17432576 (16.625MB)
   used     = 177872 (0.1696319580078125MB)
   free     = 17254704 (16.455368041992188MB)
   1.0203426045582706% used
To Space:
   capacity = 17432576 (16.625MB)
   used     = 0 (0.0MB)
   free     = 17432576 (16.625MB)
   0.0% used
concurrent mark-sweep generation:
   capacity = 874119168 (833.625MB)
   used     = 36658360 (34.96013641357422MB)
   free     = 837460808 (798.6648635864258MB)
   4.193748557633734% used

26258 interned Strings occupying 3039944 bytes.

分析年轻代和年老代占用内存占有；

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jmap -history:live 6055 | more

用于分析耗费内存比较大的对象，确认是否有不断创建对象的线程，或资源池未进行关闭

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确认资源是否耗尽

pstree

4. 线程block、线程数暴涨

jstack -l pid |wc -l

jstack -l pid |grep "BLOCKED"|wc -l

jstack -l pid |grep "Waiting on condition"|wc -l

线程block问题一般是等待io、等待网络、等待监视器锁等造成，可能会导致请求超时、造成造成线程数暴涨导致系统502等。

如果出现这种问题，主要是关注jstack 出来的BLOCKED、Waiting on condition、Waiting on monitor entry等状态信息。

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