There is always this old chestnut
http://wiki.apache.org/cassandra/FAQ#ubuntu_hangs
A
-
Aaron Morton
Freelance Cassandra Developer
New Zealand
@aaronmorton
http://www.thelastpickle.com
On 16/02/2013, at 8:22 AM, Edward Capriolo edlinuxg...@gmail.com wrote:
With hyper threading a core can show up as two or maybe even four
physical system processors, this is something the kernel does.
On Fri, Feb 15, 2013 at 11:41 AM, Hiller, Dean dean.hil...@nrel.gov wrote:
We ran into an issue today where website became around 10 times slower. We
found out node 5 out of our 6 nodes was hitting 2100% cpu (cat /proc/cpuinfo
reveals a 16 processor machine). I am really not sure how to hit 2100%
unless we had 21 processors. It bounces between 300% and 2100% so I tried
to a do a thread dump and had to use –F which then hotspot hit a nullpointer
:(.
I copied off all my logs after restarting(should have done it before
restarting it). Any ideas what I could even look for as to what went wrong
with this node?
Also, we know our astyanax for some reason is not setup properly yet so we
probably would not have seen an issue had we had all nodes in the seed
list(which we changed today) as astyanax is supposed to be measuring time
per request and changing which nodes it hits but we know it only hits nodes
in our seedlist right now as we have not fixed that yet. Our astyanax was
hitting 3,4,5,6 and did not have 1 and 2 in the seed list (we rollout a new
version next wed. with the new seedlist including the last two delaying the
dynamic discovery config we need to look at).
Thanks,
Dean
Commands I ran with jstack that didn't work out too well….
[cassandra@a5 ~]$ jstack -l 20907 threads.txt
20907: Unable to open socket file: target process not responding or HotSpot
VM not loaded
The -F option can be used when the target process is not responding
[cassandra@a5 ~]$ jstack -l -F 20907 threads.txt
Attaching to process ID 20907, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 20.7-b02
java.lang.NullPointerException
at
sun.jvm.hotspot.oops.InstanceKlass.computeSubtypeOf(InstanceKlass.java:426)
at sun.jvm.hotspot.oops.Klass.isSubtypeOf(Klass.java:137)
at sun.jvm.hotspot.oops.Oop.isA(Oop.java:100)
at sun.jvm.hotspot.runtime.DeadlockDetector.print(DeadlockDetector.java:93)
at sun.jvm.hotspot.runtime.DeadlockDetector.print(DeadlockDetector.java:39)
at sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:52)
at sun.jvm.hotspot.tools.StackTrace.run(StackTrace.java:45)
at sun.jvm.hotspot.tools.JStack.run(JStack.java:60)
at sun.jvm.hotspot.tools.Tool.start(Tool.java:221)
at sun.jvm.hotspot.tools.JStack.main(JStack.java:86)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at sun.tools.jstack.JStack.runJStackTool(JStack.java:118)
at sun.tools.jstack.JStack.main(JStack.java:84)
[cassandra@a5 ~]$ java -version
java version 1.6.0_32
