Hello I have tomcat6 as a windows server.
I am considering increasing the mmeory but I am not sure how much memory it currently has.
It is run as a service and there is a "Configure Tomcat" icon in the start menu
This has a java-tab with "Initial memory pool" and "Maximum memory pool" both of which are empty. What is the default on these?
There are also some Java Options:
-Djava.io.tmpdir=C:\Tomcat6\temp
-Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager
-Djava.util.logging.config.file=C:\Tomcat6\conf\logging.properties
By default Tomcat 6 is configured to use a minimum of 64 MB of RAM and a maximum of 128 MB of RAM allocated to the heap.
I would suggest to increase the max memory pool to at least 1024 MB. This could be increased, depending upon your server needs.
If you want to increase the Permanent Generation memory, you can add this in a separate line in the Java Options text area :
-XX:MaxPermSize=128m
Related
What is the usual recommended heap memory setting for a production environment, 1 microservice written in Java, if compiled as a native image using GraalVM Community Edition? Should I specify both -xms and -xms to keep the minimum heap and maximum heap size the same?
There is no recommendation from documentation, it says
Java Heap Size
When executing a native image, suitable Java heap settings will be determined automatically based on the system configuration and the used GC. To override this automatic mechanism and to explicitly set the heap size at run time, the following command-line options can be used:
-Xmx - maximum heap size in bytes
-Xms - minimum heap size in bytes
-Xmn - the size of the young generation in bytes
See here for full document. JVM memory management is an old topic discussed many times before
how to choose the jvm heap size?
java - best way to determine -Xmx and -Xms required for any webapp & standalone app
long story short for any application there is no "one" number. Some application may require 4GB some require 64GB depends to the "load" and data used per request(webapp) or OS(win/linux) app runs on. After you monitor the app sometime you can decide. It is not easy so that's why people are going serverless lately.
I want to increase the Java heap size from the default 512mb to 24g, so that my 250 GB ram server is optimally utilized by neo4j. I tried changing the -Xms512m value in the neo4j.vmoptions file to -Xm24000m but neo4j fails to start with heap too big error?!?!
I checked that I have more than 150GB free memory at that time. If I change it to 1024 it works and anything more or fails to start.
I'm using 64 bit java on 64bit windows.
Any help on how to increase the heap size to 24GB!? My db size on disk is 10Gb
Update
I've configured both xms (initial memory) and xmx (maximum memory allocation jvm paramters, after a restart i've hooked up Visual VM to monitor the Tomcat memory usage. While the indexing process is running, the memory usage of Tomcat seems ok, memory consumption is in range of defined jvm params. (see image)
So it seems that filesystem buffers are consuming all the leftover memory, and does not drop memory? Is there a way handle this behaviour, like change nGram size or directoryFactory?
I'm pretty new to Solr and Tomcat, but here we go:
OS Windows server 2008
4 Cpu
8 GB Ram
Tomcat Service version 7.0 (64 bit)
Only running Solr
No optional JVM parameters set, but Solr config through GUI
Solr version 4.5.0.
One Core instance (both for querying and indexing)
Schema config:
minGramSize="2" maxGramSize="20"
most of the fields are stored = "true" (required)
Solr config:
ramBufferSizeMB: 100
maxIndexingThreads: 8
directoryFactory: MMapDirectory
autocommit: maxdocs 10000, maxtime 15000, opensearcher false
cache (defaults): filtercache initialsize:512 size: 512 autowarm: 0
queryresultcache initialsize:512 size: 512 autowarm: 0
documentcache initialsize:512 size: 512 autowarm: 0
We're using a .Net Service (based on Solr.Net) for updating and inserting documents on a single Solr Core instance. The size of documents sent to Solr vary from 1 Kb up to 8Mb, we're sending the documents in batches, using one or multiple threads. The current size of the Solr Index is about 15GB.
The indexing service is running around 3 a 4 hours to complete all inserts and updates to Solr. While the indexing process is running the Tomcat process memory usage keeps growing up to > 7GB Ram and does not reduce, even after 24 hours.
After a restart of Tomcat, or a Reload Core in the Solr Admin the memory drops back to 1 a 2 GB Ram. Memory leak?
Is it possible to configure the max memory usage for the Solr process on Tomcat?
Are there other alternatives? Best practices?
Thanks
You can setup JVM memory setting on tomcat. I usually do this with setenv.bat file in bin directory of tomcat (same directory as the catalina.bat/.sh files are).
Adjust following values as per your needs:
set JAVA_OPTS=%JAVA_OPTS% -Xms256m -Xmx512m"
Here are clear instruction on it:
http://wiki.razuna.com/display/ecp/Adjusting+Memory+Settings+for+Tomcat
At first you have to set XMX parameter to limit maximum memory that can be used by Tomcat. But in case of SOLR you have to remember that it uses a lot of memory outside of JVM to handle filesystem buffers. So never use more than 50% of available memory for Tomcat in this case.
I have the following setup (albeit a much smaller problem)...
5000 documents, document sizes range from 1MB to 30MB.
We have a requirement to run under 1GB for the Tomcat process on a 2 CPU / 2GB system
After bit of experimentation I came up with these settings for JAVA.
-Xms448m
-Xmx768m
-XX:+UseConcMarkSweepGC
-XX:+UseParNewGC
-XX:ParallelCMSThreads=4
-XX:PermSize=64m
-XX:MaxPermSize=64m
-XX:NewSize=384m
-XX:MaxNewSize=384m
-XX:TargetSurvivorRatio=90
-XX:SurvivorRatio=6
-XX:+CMSParallelRemarkEnabled
-XX:CMSInitiatingOccupancyFraction=55
-XX:+UseCMSInitiatingOccupancyOnly
-XX:+OptimizeStringConcat
-XX:+UseCompressedOops
-XX:MinHeapFreeRatio=5
-XX:MaxHeapFreeRatio=5
These helped but I encountered issues with the OutOfMemory and Tomcat using too much memory even with such a small dataset.
Solution Or things/configuration I have set so far that seem to hold well are as follows:
Disable all caches other than QueryResultCache
Do not include text/content fields in your query only include the id
Do not use row size greater than 10 and do not include highlighting.
If you are using highlighting (this is the biggest culprit), get the document identifiers from the query first and then do the query again with highlighting and the search terms with the id field included.
Finally for the memory problem. I had to grudgingly implement an unorthodox approach to solve the tomcat/java memory hogging issue (as java never gives back memory to the OS).
I created a memory governor service that runs with debug privilege and calls windows API to force tomcat process to release memory. I also have a global mutex to prevent access to tomcat while this happens when a call comes in.
Surprisingly this approach is working out well but not without its own perils if you do not have the option to control access to Tomcat.
If you find a better solution/configuration changes please let us know.
I have a high end machine with 32 GB and I want to effectively utilize the available RAM for Java Process. Practically, I have seen I can run at max 3 JBoss instances (or Java Process) with Max 3GB Heap Size in one box still I have 20GB free space not utilized. Is it possible to create Java Program that can effectively directly work with RAM like C++, not relying on Java Memory Model for creating objects on JVM and also not relying on GC to reclaim memory. I mean Java Program directly working with RAM
On startup of Jboss EAP 6 server, because of static caching the heap size increases to more than 4096M while same application hosted on Jboss 5 GA heap size does not exceed 2000M.
I am using following VM arguments to boot the server.
-server -Xms1024M -Xmx4096M -XX:MaxPermSize=1024M -Dsun.rmi.dgc.client.gcInterval=3600000 -Dsun.rmi.dgc.server.gcInterval=3600000
Is there a different GC strategy involved in getting Jboss 6 Heap 6 increase.
Thanks
You can check the GC algorithm using jmap -heap of the JVM. But it does not make sense, memory utilization is purely based on the application requirement. If you had 2GB of heap in your previous JBoss version, certainly with same load, and other VM arguments then either your infrastructure would have deployed an limiting factor ( for example thread pool configuration) or your application would have given OOME.
"Is there a different GC strategy involved in getting Jboss 6 Heap 6 increase."
To add a note on above line, JBoss does not decide what GC algorithm should be adopted for your application. Its the Java (JRE) who decides (until and unless you direct it to particular configuration). Java decides based on the server, OS configuration.
JBoss will only comes with default min and max heap and perm size .. rest is all dependent on the Java you are using.