Coldfusion Multi instance Memory Issues

Report · Aug 06, 2009

Hello, we recently got brand new servers with 8gb of ram and 64bit Windows 2008. We have about 7 instances created on these servers and I am noticing something extremely disturbing. On 2 of the instances which I just created today that have absolutely no sites running on them yet as we are still migrating sites. Coldfusion immediately consumes 700 to 900 mb of working set memory. this is for all instances which then makes my server seem like it is out of memory. on the old box it only took the about of working memory that is needed and this would grow over time but not immediately upon starting the server. I started on of these instances and litterally watched as it took 850mb of ram within 2 minutes of starting and it doesn't get released.

I do have the jvm set to 2gb and they do for now all share the same jvm. I am just curious if anyone else running 64bit Windows 2008 is having the same issue and if it is just normal behavior with 64bit systems. We moved to these beefy servers to help with memory issues but it seems I am still plauged with the issue even when there is no site allocated to the instance.

Any ideas and thoughts would be appreciated.

thank you.

Report · Aug 06, 2009

If you have a min memory parameter in your jvm.config (-xmxMin or somethingn like that, then each instance on start will immediately reserve that amount of memory.

This is a java thing not CF. With CF8, I don't think having the min memory value matters with the most recent java versions. I previous versions you would occasionally get out of memory errors if you didn't, but I haven't heard of this since CF8 came out.

They may have also fixed something in 8 to help alleviate that issue.

So chaulk it up as normal. With 7 instances you'll probably run into more CPU issues.

Byron Mann

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byronosity@gmail.com

Software Architect

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Report · Aug 11, 2009

You can try setting your -Xms=128m and see if that helps any.

Not sure, myself. We set -Xms and -Xmx=4096m across three instances.

I wouldn't be too worried about it. If you're not using those instances, stop them so they're not consuming memory for no reason.