what do 'jmap' and 'jmap -histo:live' show?.
Raghu.
Stefan Will wrote:
Chris,
Thanks for the tip ... However I'm already running 1.6_10:
java version "1.6.0_10"
Java(TM) SE Runtime Environment (build 1.6.0_10-b33)
Java HotSpot(TM) 64-Bit Server VM (build 11.0-b15, mixed mode)
Do you know of a specific bug # in the JDK bug database that addresses this
?
Cheers,
Stefan
From: Chris Collins <ch...@scoutlabs.com>
Reply-To: <core-user@hadoop.apache.org>
Date: Fri, 8 May 2009 20:34:21 -0700
To: "core-user@hadoop.apache.org" <core-user@hadoop.apache.org>
Subject: Re: Huge DataNode Virtual Memory Usage
Stefan, there was a nasty memory leak in in 1.6.x before 1.6 10. It
manifested itself during major GC. We saw this on linux and solaris
and dramatically improved with an upgrade.
C
On May 8, 2009, at 6:12 PM, Stefan Will wrote:
Hi,
I just ran into something rather scary: One of my datanode processes
that
I¹m running with Xmx256M, and a maximum number of Xceiver threads
of 4095
had a virtual memory size of over 7GB (!). I know that the VM size
on Linux
isn¹t necessarily equal to the actual memory used, but I wouldn¹t
expect it
to be an order of magnitude higher either. I ran pmap on the
process, and it
showed around 1000 thread stack blocks with roughly 1MB each (which
is the
default size on the 64bit JDK). The largest block was 3GB in size
which I
can¹t figure out what it is for.
Does anyone have any insights into this ? Anything that can be done to
prevent this other than to restart the DFS regularly ?
-- Stefan
