Mar 17
TL;DR: Java and cgroups/Docker memory constraints don’t always behave as you might expect. Always explicitly specify JVM heap sizes. Also be aware that kernel features may not be enabled. And Linux… lies. I’ve recently discovered an interesting “quirk” in potential interactions between Java, cgroups, Docker, and the kernel which can cause some surprising results. Unless …
Mar 15
TL;DR — When using AUFS in a memory constrained environment, Java can spawn (lots!) of Zombies. A workaround is to change the storage driver to the device mapper. In working on the Hadoop in a box CDH cluster with Cloudera Manager, I’ve discovered a few interesting things about AUFS. These experiences are with Ubuntu 14.04 …
Nov 30
I’m one of the lucky folk who was able to obtain a Raspberry Pi Zero for $5. Originally this was going to be an article reviewing the Pi Zero to see how much of a difference the overclocking really makes. That and my impressions of the Zero will be in a later post. TL;DR: The …
Oct 02
Java’s twenty years old now — next year Duke can have Irish Coffee! Seriously, though, in that time there’s been a lot of changes to the Java Virtual Machine (JVM). What once was true may no longer be the case. In digging into an issue I discovered a nice feature of the JVM which enables …
© 2008-2016 by Matthew K. Williams
Ramblings by Matt Williams is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Based on a work at http://matthewkwilliams.com.
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