jvm monitoring

This article is intended to give a conceptual introduction to all of the students who want to learn about the JVM (Java Virtual machine), mainly on the components of the JVM and the mechanics and principles of their internal workings. Of course this article is just a simple introduction, will not involve too many complicated parameters and configuration, interested students can do more in-depth research, in

is divided evenly into three parts, the eldest brother occupies two, and the younger generation occupies a copy. Reference Sun Java System application Server Enterprise Edition 8.2 Performance Tuning guide), this ratio is not suitable for all situations, especially when local variables in your application are far greater than the global variables, and a large number of local variables have a short life cycle. How to reasonably configure the proportion xx:newratio values of the young generation

Directory I understand the monitoring Code exception Monitoring Remote Host Configuration Jmx Modify the Java program startup parameters (Jvm_opts) to start. Modify file Permissions Start JVISUALVM Monitoring Java programs on the server JSTATD connecting to a remote JVM

this, I will repost some suggestions on memory management from richen Wang, a tech-savvy guy --1. manually set the generated useless object and the intermediate object to null to accelerate memory recovery.2. Object pool technology if the generated object is a reusable object, but its attributes are different, you can use the object pool to generate fewer objects. If there are idle objects, they will be taken out and used from the object pool, without generating new objects, which greatly impro

recovery of memory, you may consider using the JVM tuning method to solve, but must go through the physical machine long-term testing, because different parameters may cause different effects. such as-XNOCLASSGC parameters.Two recommended memory detection tools1, Jconsole JDK comes with memory monitoring tool, path JDK bin directory under Jconsole.exe, double-click to run. There are two ways to connect, th

Tomcat needs to be optimized, and there are no 2GB restrictions on the 64-bit OS, either system memory or the JVM.For JMX remote monitoring is also set here, the following is configured in a 64-bit system environment.These configurations can basically be achieved by:The system response time increases rapidly;The JVM recovery speed increases without affecting the system response rate;Maximum

space.VISUALVM Visual GC plugin diagram in the official JDK monitoring tool:4), under what circumstances trigger garbage collectionIn general, when a new object is generated and the Eden application space fails, the minor GC is triggered, GC is performed on the Eden Zone, the non-surviving objects are cleared, and the surviving objects are moved to the survivor area. Then tidy up the two districts of survivor. This method of GC is carried out on the

constantly updated!Iv. Frequently Asked Questions1. Memory OverflowIs that you require the allocation of the Java Virtual Machine memory beyond the system can give you, the system can not meet the requirements, so overflow.2. Memory leaksIs that you apply to the system to allocate memory for use (new), but after use is not returned (delete), the result of the memory you have applied to your own can no longer access, the block has been allocated to the memory can no longer be used, as the server

Java built-in performance monitoring tool: Monitoring and Management Console jconsole usage1. Would you like to verify whether some tuning parameters (such as Xms and Xmx) configured for the jvm work? Do you want to monitor the number of threads in your custom thread pool in real time? Is there a deadlock? Java. lang. OutOfMemoryError: Java heap space appears in

Global-Global JNI reference Monitor used -monitoring objects for synchronization Held by JVM -objects reserved for the special purpose of the JVM by the GC, but this is actually related to the implementation of the JVM. Some of the types that may be known are the system ClassLoader, the important exception classes

collector also stops other processes, but uses multithreading to accelerate the collection process. Although it is easier to cause long-time interruptions than other collectors, it can generally make better use of memory and program efficiency. By default, jrockit uses the generational concurrent collector. To change the collector, use-xgc:. The four collectors are gencopy, singlecon, GENCON, and parallel. You can use-XMS and-xmx to set the initial size and maximum value of the heap. To set the

bridge, there is only one lane on the bridge, all cars must be passed from this bridge. SoThe system load is 0, which means there's no car on the bridge.System load 0.5 means there's a car on half the bridge section.System load of 1 means that the road on the bridge has been fully occupied by the carThe system load of 1.7, which means that the car is full on the bridge (100%), while 70% of the car is waiting to pass through the bridge:From the top command, you can see that the three values of t

These monitors include host survival, disk space monitoring, load monitoring, process Count monitoring, and ip connection monitoring. (1) define the host configuration file hosts. cfgdefinehost {host_namecacti.comaliasnagiosserveraddress192.168.10.195contact_groupsadmin on the moni