tag:help-archives.hannonhill.com,2010-02-09:/discussions/installation/3929-maximum-memory-allocatedCascade CMS: Discussion 2015-03-16T12:48:33Ztag:help-archives.hannonhill.com,2010-02-09:Comment/358815282015-01-26T19:11:08Z2015-01-26T19:11:08ZMaximum Memory Allocated<div><p>Hi Justin,</p>
<p>There isn't any hard maximum, but it's not always best to set a
huge maximum heap size (because that can lead to longer garbage
collections for the JVM). How much RAM are you currently allocating
and how much total RAM is available on your application server?</p>
<p>Are you currently seeing any Out of Memory errors in the log
files in your instance or are you just curious about increasing the
allocation?</p>
<p>Thanks!</p></div>Timtag:help-archives.hannonhill.com,2010-02-09:Comment/358815282015-01-27T20:51:45Z2015-01-27T20:51:45ZMaximum Memory Allocated<div><p>Good afternoon Tim,</p>
<p>We are currently only allocating 4GB, out of a total 16GB on the
server. We aren't getting any Out of Memory errors in the log, we
are just trying to make sure the system has enough resources for
any potential spikes in activity so (hopefully) we can avoid any
errors before they happen.</p>
<p>In your experience, at what point does the extra memory start to
bog down the garbage collection? Will leaving the initial heap size
to something smaller help to alleviate this at all, or is it better
practice to keep the initial and maximum heap sizes closer
together?</p>
<p>Also of note (I meant to specify this in the initial post) but
we are using 64 bit Java on this instance of Cascade, so we
don’t have to worry about running into the ~1400MB maximum
that comes with using 32 bit Java.</p>
<p>Thank you!</p>
<p>Justin Rogers<br>
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public disclosure.</p></div>Justin Rogerstag:help-archives.hannonhill.com,2010-02-09:Comment/358815282015-01-27T21:06:26Z2015-01-27T21:06:26ZMaximum Memory Allocated<div><p>Thanks for the additional information, Justin.</p>
<blockquote>
<p>In your experience, at what point does the extra memory start to
bog down the garbage collection? Will leaving the initial heap size
to something smaller help to alleviate this at all, or is it better
practice to keep the initial and maximum heap sizes closer
together?</p>
</blockquote>
<p>It's difficult to say as it will really depend on your
implementation along with the number of users in your system (along
with what they are doing at any given time). In general, I think
it's best to keep the initial and maximum heap sizes the same, but
you may need to tune these settings once you get above 6GB or so
for the heap size (by setting the Xms a bit lower than the Xmx).
The scenario you want to avoid is where the JVM will pause
everything in order to do a full garbage collection. This can
happen if the heap is set to something much larger than it needs to
be. So, I'd recommend monitoring the instance to see if you are
ever running out of memory altogether over a span of a couple of
weeks. If you aren't, and you aren't noticing any performance
issues in the system, you should be fine with your current
settings.</p>
<p>If you feel that memory issues might be causing performance
problem in your instance, it's possible to enable garbage
collection logging which would provide us with more information as
to how often garbage collections might be occurring (along with how
successful they are). We can go that route if you begin running
into issues.</p>
<p>We include a monitoring tool (Java Melody) with the application
beginning with version <a href=
"http://www.hannonhill.com/kb/Release-Notes/7.12.3/index.html#notes">
7.12.3</a>. This may help assist you all in seeing how your
instance is performing over periods of time.</p>
<p>I hope this helps!</p>
<p>Thanks</p></div>Tim