[TriLUG] Memory Monitor on a Redhat system

[Tim Jowers]

   Ideas: One other silly but possible thing is to try to start another Java
app than JBoss. Java is not enterprise-ready yet with its mem size and is
basically limited to 3G of user space per VM so you have to run several
instances on large RAM machines (at least that's what a BEA consultant told
me ;-).  Also, does "sync" help to free up any space? You can also set
swapoff to speed up the problem or even limit the RAM during boot with a
kernel parameter in GRUB etc. Last of all, in BEA a few years back I saw a
mem alloc exception which was actually due to a mismatch between the AIX
system calls and the java runtime code. We just changed the Java code to
execute another set of system calls.

TimJowers


On 3/29/07, Len Boyle <Len.Boyle at sas.com> wrote:
>
> How much swap space do you have defined on disk?
> On Solaris the os reserve space in main memory for possible swap usage if
> there is none available on disk. I do not know if Red Hat does the same
> thing, but it is something that you might look at.
>
> len
>
> -----Original Message-----
> From: trilug-bounces at trilug.org [mailto:trilug-bounces at trilug.org] On
> Behalf Of Robert Dale
> Sent: Thursday, March 29, 2007 2:18 PM
> To: Triangle Linux Users Group discussion list
> Subject: Re: [TriLUG] Memory Monitor on a Redhat system
>
> On 3/29/07, Tom Le <t.thanhcle at gmail.com> wrote:
> > We are having problems with memory usage on a Redhat AS 4 - on a
> > 64-bit Power PC IBM pSeries. We was wondering if there is a reliable
> > package to monitor memory usage on the server. Our current problem is
> > that the system memory is 95% capacity and we have no idea what is
> > taking up all the memory. We are certain that oracle is using 1G out
> > of 16G of the box, and one instance of jboss is set to use max 1G of
> > memory. We are trying to add a second instance of jboss and it won't
> > start due to insufficient memory. We need a package or a way to drill
> > down to what application using how much memory on the server Any
> > suggestion is appreciated.
>
> When you say at 95% capacity is that including buffers and cache?
>
> What's your actual memory usage?  (/proc/meminfo would be useful here)
> MemTotal - MemFree - Buffers - Cached = actual used memory
>
> What's the actual jboss error message?  Do you have the jvm stacktrace?
> What jvm are you using?  What jvm options are you starting jboss with?
>
> --
> Robert Dale
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