# vmoption [`vmoption`在线教程](https://arthas.aliyun.com/doc/arthas-tutorials.html?language=cn&id=command-vmoption) ::: tip 查看，更新 VM 诊断相关的参数 ::: ### 使用参考 #### 查看所有的 option ```bash [arthas@56963]$ vmoption KEY VALUE ORIGIN WRITEABLE --------------------------------------------------------------------------------------------- HeapDumpBeforeFullGC false DEFAULT true HeapDumpAfterFullGC false DEFAULT true HeapDumpOnOutOfMemory false DEFAULT true Error HeapDumpPath DEFAULT true CMSAbortablePrecleanW 100 DEFAULT true aitMillis CMSWaitDuration 2000 DEFAULT true CMSTriggerInterval -1 DEFAULT true PrintGC false DEFAULT true PrintGCDetails true MANAGEMENT true PrintGCDateStamps false DEFAULT true PrintGCTimeStamps false DEFAULT true PrintGCID false DEFAULT true PrintClassHistogramBe false DEFAULT true foreFullGC PrintClassHistogramAf false DEFAULT true terFullGC PrintClassHistogram false DEFAULT true MinHeapFreeRatio 0 DEFAULT true MaxHeapFreeRatio 100 DEFAULT true PrintConcurrentLocks false DEFAULT true ``` #### 查看指定的 option ```bash $ vmoption PrintGC KEY VALUE ORIGIN WRITEABLE --------------------------------------------------------------------------------- PrintGC false MANAGEMENT true ``` #### 更新指定的 option ```bash $ vmoption PrintGC true Successfully updated the vm option. NAME BEFORE-VALUE AFTER-VALUE ------------------------------------ PrintGC false true ``` ```bash $ vmoption PrintGCDetails true Successfully updated the vm option. NAME BEFORE-VALUE AFTER-VALUE ------------------------------------------- PrintGCDetails false true ```