[chef] RE: Re: Re: Re: Re: [ANN] jvmargs, a sanity checker for JVM options

[Adam Jacob < >]

Even if it is true - no need to force it. Have a happy path that does what 
you say, and a "no really" path. :)

Adam

-----Original Message-----
From: Bryan Berry 
[mailto:
 
 
Sent: Thursday, March 21, 2013 6:49 AM
To: 

 
Subject: [chef] Re: Re: Re: Re: [ANN] jvmargs, a sanity checker for JVM 
options

well I can definitely be horribly mistaken on the matching Xmx and Xms
:) , and am willing to change the  code

iirc I read the matching Xmx and Xms in the "Java Performance" book but I 
could be mistaken

On Thu, Mar 21, 2013 at 2:44 PM, Jesse Campbell 
<
 >
 wrote:
> I've read plenty that suggests that depending on the situation, having 
> different Xms and Xmx values can be beneficial.
>
> i've seen things like this:
> http://java-monitor.com/forum/showthread.php?t=427
> which suggest that setting them the same has no particularly 
> beneficial effect.
>
> and I've seen things like this:
> http://weblogs.java.net/blog/kcpeppe/archive/2011/12/19/setting-xmx-xm
> s-still-considered-harmful which suggest that the ideal settings are 
> for xms to be your 99% case, and xmx allow for some wiggle room
>
> in fact, i haven't seen any really good recent analyses that support 
> setting them the same, just lots of rhetoric
>
> -jesse
>
>
> On Thu, Mar 21, 2013 at 9:31 AM, Bryan Berry 
> <
 >
>  wrote:
>>
>> min and max should be the same because there is no benefit to having 
>> a lower min according to everything I have read. It can slow down 
>> your application startup however.
>>
>> it will not support parsing a space delimited string, only the 
>> options specifically for the JVM, for example
>>
>> "java  -Djava.io.tmpdir=/tmp/foo -server -Xmx256m -Xint 
>> -XX:MaxPermSize=512M -classpath /tmp/foo.jar:/tmp/baz.jar 
>> org.apache.catalina.Bootstrap start "
>>
>> jvmargs doesn't add the java binary to the beginning nor the 
>> "org.apache.catalina.Bootstrap start"
>>
>> I do want to handle the classpath but i have not figured out a clean 
>> way to handle that yet :(
>>
>> i would very much appreciate feedback and testing. this afternoon i 
>> hope to add support for arbitrary rules like the following
>>
>> "if Max heap is greater than available RAM, raise an error"
>> "if Max heap is changed, also set Min heap to same value"
>>
>> On Thu, Mar 21, 2013 at 2:18 PM, Jesse Campbell 
>> <
 >
>>  wrote:
>> > hey, been looking for something like this to come along, looks like 
>> > a very clean, sane way to handle it :D
>> >
>> > in your todo you have ensure min and max heap should be the same. 
>> > why is this?
>> >
>> > i didn't dig to far into the code, but will it support parsing a 
>> > space delimited string, as the current tomcat and tomcat6 cookbooks 
>> > expect, or will the cookbook be expected to handle that?
>> >
>> > thanks!
>> >
>> >
>> > On Thu, Mar 21, 2013 at 4:53 AM, Bryan Berry 
>> > <
 >
>> > wrote:
>> >>
>> >> hey folks,
>> >>
>> >> i have written a little gem to parse JVM options and would love 
>> >> some feedback on it. Managing JVM options in a cookbooks is a 
>> >> total PITA and I hope this makes it easier. This is less than 
>> >> alpha quality, i am posting it here to get some feedback, not to 
>> >> notify others of a production-ready tool. I foresee it being used 
>> >> in Java-related cookbooks to provide a set of application-specific 
>> >> defaults and then make it easy to override or add to them in recipe 
>> >> code.
>> >>
>> >> https://github.com/bryanwb/jvmargs
>> >>
>> >> This library parses JVM options so that any given option is only 
>> >> stored once. It does this by breaking each option into one of the 
>> >> three option categories:
>> >>
>> >> 1. standard, ex: -server, -enablesystemassertions 2. nonstandard, 
>> >> ex: -Xmx128M, -Xint 3. unstable, ex: -XX:-DisableExplicitGC, 
>> >> -XX:AltStack=128M 4. directive, ex: -Dcom.sun.management.jmxremote
>> >>
>> >> JVMArgs will ensure that only one value is stored for any given 
>> >> option. Here is a quick example
>> >>
>> >> args = JVMArgs::Args.new("-XX:-DisableExplicitGC", "-Xmx256M") # 
>> >> "-XX:-DisableExplicitGC" is now stored in args
>> >> args.add("-XX:+DisableExplicitGC")
>> >> args.add("-Xmx2G")
>> >> # the settings are now "-XX:+DisableExplicitGC" and "-Xmx2G"
>> >
>> >
>
>