| From: Christopher Schultz [mailto:[EMAIL PROTECTED]
| Sent: Wednesday, 14 March, 2007 15:02
|
| In my tests on the larger machine, the JVM kindly tells me that it can't
| give me that much memory, rather than crashing and burning as I would
| expect after being tricked by the OS.
Perhaps the JV
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Tracy,
Nelson, Tracy M. wrote:
> I imagine that when the JVM calls [cm]alloc, one of the first things alloc()
> does is call sbrk() to expand your process' memory space. That'll fail
> right away if you don't have enough VM available.
I do not exper
| From: Christopher Schultz [mailto:[EMAIL PROTECTED]
| Sent: Wednesday, 14 March, 2007 12:05
|
| Perhaps, but the JVM actually refuses to start right away. In my "eat
| all my memory" tests, I was able to eat around 1.6GB before I brought my
| machine to a crawl. It took more than a minute for my
> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> For instance, "java -Xmx512M -Xms512M -version" bombs on this little
> box, even though the heap is pretty much never used.
Th
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Tracy,
Nelson, Tracy M. wrote:
> | From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> | Sent: Wednesday, 14 March, 2007 10:37
> |
> | The fact remains that you can't allocate a VM heap bigger than around
> | 1750MB on my 32-bit, 2.6 Linux kernel.
| From: Christopher Schultz [mailto:[EMAIL PROTECTED]
| Sent: Wednesday, 14 March, 2007 10:37
|
| The fact remains that you can't allocate a VM heap bigger than around
| 1750MB on my 32-bit, 2.6 Linux kernel. Why not?
If, as you stated earlier, you only have 1G of physical and 1G of virtual
memor
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Chuck,
Caldarale, Charles R wrote:
>> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
>> Subject: Re: [OT]Re: Is better one or more Tomcat instances
>> per machine
>>
>> The fact remains that you can't al
> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> The fact remains that you can't allocate a VM heap bigger than around
> 1750MB on my 32-bit, 2.6 Linux kernel. Why not?
You have
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Chuck,
Caldarale, Charles R wrote:
>> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
>> Subject: Re: [OT]Re: Is better one or more Tomcat instances
>> per machine
>>
>> I guess that Linux not only does optimistic
> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> I guess that Linux not only does optimistic malloc, but also
> optimistic calloc as well. I had hoped that zeroing-out the
> memory wo
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Andrew,
Andrew Miehs wrote:
> On 14/03/2007, at 3:17 PM, Peter Crowther wrote:
>> A minor advantage is that if you allocate one webapp per container, if
>> one webapp fails it only takes down its own container. Well-coded
>> webapps "should" never ca
Heh - ask Murphy about that :)
just spawn a thread set priority high and loop forever.
At 10:23 3/14/2007, you wrote:
On 14/03/2007, at 3:17 PM, Peter Crowther wrote:
From: Leon Rosenberg [mailto:[EMAIL PROTECTED]
There is no real advantage in multi-instancing.
A minor advantage is that if
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Chuck,
Caldarale, Charles R wrote:
>> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
>> Subject: Re: [OT]Re: Is better one or more Tomcat instances
>> per machine
>>
>> I don't think this has anything to d
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Chuck,
Caldarale, Charles R wrote:
>> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
>> Hmm perhaps I have a virtual memory limit. I have 1GB
>> of physical RAM. While allocating a 3GB heap is pretty
>> stupid for me, I still ought to be a
> From: Andrew Miehs [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> Your kernel, and the things which are doing your process
> switching need somewhere to run - if you switch them out
> of your 4GB of virtual a
> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> Hmm perhaps I have a virtual memory limit. I have 1GB
> of physical RAM. While allocating a 3GB heap is pretty
> stupid for me, I stil
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 14/03/2007, at 3:52 PM, Caldarale, Charles R wrote:
The user space is the amount of RAM you as a process can
allocate for this single process.
No - RAM has nothing to do with the split. Process memory is the
amount
of virtual space allocated
of ram, I will test it
as soon as I get some time.
Andrew Pliszka
Caldarale, Charles R wrote:
From: Andrew Miehs [mailto:[EMAIL PROTECTED]
Subject: Re: [OT]Re: Is better one or more Tomcat instances
per machine
The user space is the amount of RAM you as a process can
allocate for this
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Andrew,
Andrew Miehs wrote:
> 32bit OSes can not use more than 4GB RAM.
??!
A process on a 32-bit OS can't use more than 4GB of RAM, but the OS
certainly can.
>> 2GB/2GB kernel and process memory boundaries (they don't, except that I
>> think MS Wi
> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> I don't think this has anything to do with hardware.
It does. To quote from the IA32 architecture spec:
"Starting with the Pentium
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Chuck,
I knew you'd come through. It's always nice to have a VM hacker around
for questions like this.
Caldarale, Charles R wrote:
>> that they have 2GB/2GB kernel and process memory boundaries
>
> Windows certainly does have such a boundary (althou
> From: Andrew Miehs [mailto:[EMAIL PROTECTED]
> Subject: Re: [OT]Re: Is better one or more Tomcat instances
> per machine
>
> The user space is the amount of RAM you as a process can
> allocate for this single process.
No - RAM has nothing to do with the split. Process me
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
David,
David Delbecq wrote:
> 32 bits architecture, a memory pointer is 32 bits and thus can only
> address memory ranges between 0 to 2^32, that makes 4G
> back in kernel 2.4 time
Pointers didn't get bigger in 2.6, so the 4GB process limit is still
On 14/03/2007, at 3:21 PM, Peter Crowther wrote:
Let's be clear about the distinction between "OS" and "process managed
by OS":
- The OS as a whole can manage > 4 Gbytes of physical memory using
PAE;
- On some OSs (Linux, perhaps?), a user process cannot be allocated
> 4
Gbytes of RAM;
S
On 14/03/2007, at 3:17 PM, Peter Crowther wrote:
From: Leon Rosenberg [mailto:[EMAIL PROTECTED]
There is no real advantage in multi-instancing.
A minor advantage is that if you allocate one webapp per container, if
one webapp fails it only takes down its own container. Well-coded
webapps "sh
> From: Andrew Miehs [mailto:[EMAIL PROTECTED]
> 32bit OSes can not use more than 4GB RAM. What you are probably
> referring
> to is PAE, and there the kernel splits the 'extra' memory into
> chunks, and
> can give each process part of this chunk - a single process however,
> under
> linux c
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 14/03/2007, at 3:11 PM, David Delbecq wrote:
This has changed. An new architecture was brought in CPU (at
pentium II
time?) that allowed OS to do a 4G/4G mapping in 32 bits mode. Since
you
don't access kernel space from user mode directly, yo
> From: Leon Rosenberg [mailto:[EMAIL PROTECTED]
> There is no real advantage in multi-instancing.
A minor advantage is that if you allocate one webapp per container, if
one webapp fails it only takes down its own container. Well-coded
webapps "should" never cause this - and, of course, we all m
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
On 14/03/2007, at 2:31 PM, Christopher Schultz wrote:
The reading I've done so far on this subject leads me to believe that
most people don't know what they heck they're talking about. Some
claim
that 32-bit OSs can't use more than 4GB RAM (they
> From: Christopher Schultz [mailto:[EMAIL PROTECTED]
> Subject: [OT]Re: Is better one or more Tomcat instances per machine
The below applies only to 32-bit systems, of course.
> Some claim that 32-bit OSs can't use more than 4GB RAM
Lots of people seem to confuse virtual s
En l'instant précis du 14/03/07 14:31, Christopher Schultz s'exprimait
en ces termes:
> Leon,
>
> Leon Rosenberg wrote:
> > But the limit for max memory you can effectively use in your java
> > program on a 32bit linux, i assume you use (same for windows),
> > lies far below 2Gb.
>
> I've been try
-BEGIN PGP SIGNED MESSAGE-
Hash: SHA1
Leon,
Leon Rosenberg wrote:
> But the limit for max memory you can effectively use in your java
> program on a 32bit linux, i assume you use (same for windows),
> lies far below 2Gb.
I've been trying to find the real nature of this memory limit. I h
Unless you have real memory requirements, one tomcat instance is
better, at least in terms of maintenance. There is no real advantage
in multi-instancing.
But the limit for max memory you can effectively use in your java
program on a 32bit linux, i assume you use (same for windows),
lies far belo
Hi all,
I am now preparing the deployment scenario for our new webapp and I am
not sure if it is better to have one Tomcat instance per server machine
or to have more instances.
I have 3 servers - dual Intel Xeon 3GHz, 4GB RAM each (about 3GB is
available for Tomcat etc.).
There will be runn
34 matches
Mail list logo
