On 04.09.2013 05:35, Martha McConaghy wrote:
We have embarked on a project to support our main student/faculty/staff
portal
on zLinux. It works fine under a normal workload, but falls over badly
when
under a heavy load such as during class add/drop. The portal is running
open
source software named LifeRay on top of TomCat on SLES 11 SP1.
We know there is a lot of tuning that needs to be done, but there are a
ton of
variables to consider. If anyone on the list has any experience tuning
this
sort of environment, i.e. Java without Websphere, we would love to talk
with
you. Please drop me a note.
I pretty much always start with memory. GC has almost always been the
killer for performance of Java apps ever since I started working with
them, with only a handful of exceptions. Start by making sure you're
doing GC logging, check you're not using a "stop the world" collector.
For the IBM JVM I have found that if major GCs happen more than once
every 10 seconds with the gencon policy the application turns to shit -
big stalls, huge CPU use and so on. You may then need to either add
memory or look at whether your memory pools are balanced appropriately -
sometimes the default allocations to the various short and log term
pools are a poor match for your appliction.
--
Rodger Donaldson
[email protected]
----------------------------------------------------------------------
For LINUX-390 subscribe / signoff / archive access instructions,
send email to [email protected] with the message: INFO LINUX-390 or visit
http://www.marist.edu/htbin/wlvindex?LINUX-390
----------------------------------------------------------------------
For more information on Linux on System z, visit
http://wiki.linuxvm.org/
