jps 查看 java 进程 ID
[hadoop@node1 ~]$
You have mail in /var/spool/mail/root
[hadoop@node1 ~]$ jps
26276 nimbus
27238 Logstash
31017 RunJar
13579 AzkabanExecutorServer
7307 Jps
27180 Logstash
22799 NameNode
23025 SecondaryNameNode
23284 ResourceManager
19444 AzkabanWebServer
18613 core
26934 Elasticsearch
14166 HMaster
17688 Main
使用jstat查看gc的信息
jstat -gc 22799 1s 30
每秒获取一次gc信息获取三十次22799为java进程ID
参数说明：S0C：第一个幸存区的大小
S1C：第二个幸存区的大小
S0U：第一个幸存区的使用大小
S1U：第二个幸存区的使用大小
EC：伊甸园区的大小
EU：伊甸园区的使用大小
OC：老年代大小
OU：老年代使用大小
MC：方法区大小
MU：方法区使用大小
CCSC:压缩类空间大小
CCSU:压缩类空间使用大小
YGC：年轻代垃圾回收次数
YGCT：年轻代垃圾回收消耗时间
FGC：老年代垃圾回收次数
FGCT：老年代垃圾回收消耗时间
GCT：垃圾回收消耗总时间
[hadoop@node1 ~]$ jstat -gc 22799 1s 30
S0C S1C S0U S1U EC EU OC OU MC MU CCSC CCSU YGC YGCT FGC FGCT GCT
3584.0 3584.0 0.0 2560.0 1390592.0 1183261.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183261.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183270.1 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183272.2 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183272.2 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183272.2 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183272.2 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183272.2 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183300.0 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183309.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183309.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183311.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183311.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183311.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183311.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183311.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183311.4 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
3584.0 3584.0 0.0 2560.0 1390592.0 1183347.5 1051136.0 443026.8 48384.0 47434.8 5376.0 5138.6 13527 592.237 5 19.403 611.639
jmap -heap 22799
[hadoop@node1 ~]$ jmap -heap 22799
Attaching to process ID 22799, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.151-b12
using thread-local object allocation.
Parallel GC with 13 thread(s)
Heap Configuration:
MinHeapFreeRatio = 0
MaxHeapFreeRatio = 100
MaxHeapSize = 4294967296 (4096.0MB)
NewSize = 174587904 (166.5MB)
MaxNewSize = 1431306240 (1365.0MB)
OldSize = 349700096 (333.5MB)
NewRatio = 2
SurvivorRatio = 8
MetaspaceSize = 21807104 (20.796875MB)
CompressedClassSpaceSize = 1073741824 (1024.0MB)
MaxMetaspaceSize = 17592186044415 MB
G1HeapRegionSize = 0 (0.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity = 1423966208 (1358.0MB)
used = 1230129784 (1173.143180847168MB)
free = 193836424 (184.85681915283203MB)
86.38756854544683% used
From Space:
capacity = 3670016 (3.5MB)
used = 2621488 (2.5000457763671875MB)
free = 1048528 (0.9999542236328125MB)
71.42987932477679% used
To Space:
capacity = 3670016 (3.5MB)
used = 0 (0.0MB)
free = 3670016 (3.5MB)
0.0% used
PS Old Generation
capacity = 1076363264 (1026.5MB)
used = 453659472 (432.6433868408203MB)
free = 622703792 (593.8566131591797MB)
42.14743174289531% used
18933 interned Strings occupying 1911424 bytes.
