The JVM settings change the Java Runtime Environment. Java is a
virtual server and CF runs inside (or on top as many say) of that. If
the Virtual Machine is not configured for stability CF will crash and
burn with the JVM. So yes these settings alter the JVM and yes you
need to do a full CF restart. I can stop and restart each instance to
make the change take effect one by one, but a full cf restart will do
them all at once. Also, I forgot to mention before, it is best to
manually edit the jvm.config file with a text editor. You have more
control this way. And make a back up of the known good file.
As best as I can tell each instance creates it's own memory space
based on the same jvm.config file. I can not see any other file (at
this time) that creates a new instance using different settings.
This lets you get beyond the 32 bit memory addressing space if you
have enough physical ram.
CF's behavior is changed because the JVM environment which handles and
controls CF's memory usage is being altered.
Wil Genovese
One man with courage makes a majority.
-Andrew Jackson
A fine is a tax for doing wrong. A tax is a fine for doing well.
On Jun 11, 2008, at 3:53 PM, Ian Skinner wrote:
> Thanks for the suggestions, I'll try the settings. I'm curious if
> anybody can explain how this actually helps. I.E. you gave a good
> definition of each of these settings, but what does changing them
> actually do? How does the behavior of the ColdFusion Server and|or
> the
> JVM actually change when applying these settings?
>
> When I make these changes, what do I need to restart, the ColdFusion
> instance? The base 'cfusion' instance, the JRun service, the entire
> box?
>
> Speaking of instances, how does this jvm.config file play with our
> multi-home ColdFusion configuration? I somewhat expected to see
> different configuration files for each instance. My understanding was
> one of the reasons for having multiple ColdFusion was to have each one
> taking up it's defined chunk of memory, thus allowing a ColdFusion box
> to make use of more RAM then the ~2GB of RAM maximum for a 32 bit JVM
> can use.
>
> Wil Genovese wrote:
>> ok, I can help here. It is always a good idea to tune the JVM. The
>> config that come with the install is setup to allow CF to run when
>> you
>> first set it up. It was never meant to be used in production and
>> never meant for high availability. I've addressed some of these
>> issues with persons at Adobe and discussed some possible ideas to
>> help
>> their customers. Until then, try this.
>>
>> Add these settings to the args:
>> -Xms512m
>> -XX:PermSize=192m
>> -Dsun.rmi.dgc.client.gcInterval=600000
>> -Dsun.rmi.dgc.server.gcInterval=600000
>>
>> Explainations:
>> Xmx and Xms and max and min JVM memory sizes. These should always be
>> equal to each other.
>> MaxPermSize and PermSize are the permanent generation heap sizes.
>> the ..gcInterval settings are the time intervals for running the
>> garbage collector in seconds. We find that 10 minutes works just
>> fine
>> for high availability sites.
>>
>> Someone also suggested that you slow down or limit the cfthread
>> generations. Not having played with this I am not sure if it will
>> help, but it is worth a try. I'll see if I can play with thread
>> generation later today.
>>
>>
>> Wil Genovese
>>
>> One man with courage makes a majority.
>> -Andrew Jackson
>>
>> A fine is a tax for doing wrong. A tax is a fine for doing well.
>>
>> On Jun 11, 2008, at 3:22 PM, Ian Skinner wrote:
>>
>>
>>> Wil Genovese wrote:
>>>
>>>> I can help with that.
>>>>
>>>> post your java.args line from your jvm.config file.
>>>>
>>>> Wil Genovese
>>>>
>>> They are the out-of-the-box standard settings. Until now these
>>> where
>>> just fine for the simple ColdFusion applications running on our
>>> intranet.
>>>
>>> # Arguments to VM
>>> java.args=-server -Xmx512m -Dsun.io.useCanonCaches=false
>>> -XX:MaxPermSize=192m -XX:+UseParallelGC
>>> -Dcoldfusion.rootDir={application.home}/
>>>
>>> This is on a Windows 2003 server with ColdFusion 8 ( 8,0,0,176276)
>>> in
>>> multi-home configuration currently with 4 instances.
>>>
>>> The box has the following stats:
>>> 2 - 3.00GHz Intel Xeon 5160 CPUs
>>> 8GB of 2.99 GHz RAM
>>>
>>>
>>>
>>
>>
>
>
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