Limiting memory usage for Solr on Jetty

3
votes

I have a memory-limited environment and I'm running Solr on Jetty with the following command:

java -jar -Xmx64M -Xmn32M -Xss512K start.jar

But the total memory consumption of the Solr instance (or Jetty) seems to be much higher than the heap limit I provide. The output of ps is:

ps -u buradayiz -o rss,etime,pid,command

155164 01:37:40 21989 java -jar -Xmx64M -Xmn32M -Xss512K start.jar

As you see, the RSS is over 150M. How can I avoid this situation? I just want to get a simple OutOfMemory exception when Solr/Jetty uses more memory than I let them.

I understand that there may be a difference between the heap limit I provide and the actual memory usage, but a difference factor of two (actually 2.5) seems a lot to me. I must be missing something.

Thanks.

2
javamemorysolrjetty

2 Answers

5
votes

There are a number of factors that contribute to memory usage beyond the heap specification.

A major one in your situation is the permanent generation. It's used to load classes for all the dependencies required to run the application and a few other things. There's not too much getting around a certain minimum for a given application due the classes necessary. You likely need around 64M (perhaps more) to run Solr on Jetty.

You can specify a maximum size to prevent the permanent generation from growing for the other things, e.g. add -XX:MaxPermSize=64M to your command line. It's unlikely going to help much though, and it might even break it if more is required. Usually it's almost all used by classes that you need.

Another contributor to memory usage beyond the heap is the stack size per thread. Each thread in your case is going to consume 512K. You can probably specify 256K safely, although you probably don't have enough threads running to matter too much.

0
votes

I have the same problem; trying to run it in a limited environment. (Max 400mb ram/vm size). This solution seems to get it running at least.