Linux Server free memory decreases


 
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Operating Systems Linux Linux Server free memory decreases
# 8  
Old 11-28-2008
Hi
run top -i
to see name process have problem
Also see if an files in your repertory tmpfs disk
df to see if mounted and linked directory
Best regards

Last edited by bustaf; 11-28-2008 at 09:41 PM..
# 9  
Old 11-30-2008
Hi Vaibhav Agarwal,

Konerak is correct. I ask that question to before. I have 16 GB of RAM in a linux machine and all of a sudden it goes to cache but through researching to forums and website that is just normal. It will allocate available memory to cache so that application can use it.

Have you explore the settings on your JAVA apps regarding setting up memory allocated for JAVA?
# 10  
Old 12-02-2008
Try clearing memory cache - sync; echo 3 > /proc/sys/vm/drop_caches
# 11  
Old 12-02-2008
Quote:
Originally Posted by techlinux
Try clearing memory cache - sync; echo 3 > /proc/sys/vm/drop_caches
For a reference with details, see,

Free Linux Memory by Dropping Caches
# 12  
Old 12-03-2008
Again, while this command works, you only revert the linux philosophy: "idle memory is a waste". Linux puts your unused-memory to use, why would you undo that?
# 13  
Old 12-18-2008
Quote:
Originally Posted by Konerak
Cache memory is just some nix-trix: instead of "not using" memory your system doesn't need, it will use the memory to "cache data". When an application requests more memory, the kernel will free the cache if needed though, so don't worry, memory used by the cache is actually "available" for your programs.

Your java thing seems indeed to be using 2Gb of memory.. not much more I can say of that. If the java thing grows, then it's probably your java code. If the java thing always uses the same amount of memory, and something else grows, it's something else :')
As you said when an application requests for more memory the kernel will release the cached memory but I have seen the case where one Java process needs 2gb memory and around 12gb of heap space got cached and at the same time it is showing around 25mb of free space and application throws java.lang.OutOfMemoryError: Java heap space.

Can you please describe it bit more elaborately?

And also let me know how can be the cached memory release and get used during the execution of process?
# 14  
Old 12-18-2008
Hello Siba,

the kernel will automatically release the cached memory, if available. If java reports an error, perhaps you didn't start the Virtual Machine with the appropriate parameters?

If I recall correctly from my java-days, try launching the VM with the
Code:
java -Xms<initial heap size> -Xmx<maximum heap size>

command. Example:
Code:
java -Xms128m -Xmx2048m

to allocate 128Mb of memory from the start, and 2048Mb as maximum.

If you're still having problems with java memory leaks, there are toolkits out there to detect leaks in your application. I've never used any, so I suggest you use plain old google.

Happy holidays!
K.
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