4 GB RAM-based NAS

  • Thread starter Thread starter Shailesh Humbad
  • Start date Start date
I don't get what you've said is different from what I've said?
Click to expand...

I'll try to explain better then.
A poster I was replying to, apparently assumed that the total physical
memory (or even virtual) available to all applications is limited to 2 GB,
while the rest of the memory will only be used by a kernel.
Click to expand...

That was me. That is how windows pro and windows server work.
You can also read that in the links I posted.
I corrected him that every single process can get its own private 2 GB of
virtual space (the same as you've said), because other 2 GB are for OS use.
Click to expand...

That is where you are wrong.
Every process gets 2GB of virtual space. But not 2GB of real RAM!

You claimed that you can have a windows pro of windows server machine
with 8GB ram and then have 4 photoshop sessions running parallel each
using 2GB of that 8GB ram.

And that is wrong.

What will happen is that windows pro/windows server will use 2GB for
all applications in total. You will have 6GB of unused memory. The 2GB
ram that is used by windows will have to be shared among those 4
photoshop sessions that want 2GB each.
So you will have 6GB of unused memory and LOTS of paging.

So if you want to have 4 photoshop sessions each using 2GB ram running
comfortable on a 8GB ram machine, you need another OS. Either windows
adv server or higher, or a 64 bit OS.

Marc
 
What will happen is that windows pro/windows server will use 2GB for
all applications in total. You will have 6GB of unused memory. The 2GB
ram that is used by windows will have to be shared among those 4
photoshop sessions that want 2GB each.
So you will have 6GB of unused memory and LOTS of paging.
Click to expand...

Once again: Win2K Pro and Server and WinXP physical memory limit is 4 GB
(not 2 GB). Windows 2000 Advanced Server uses up to 8 GB. Physical memory is
used in uniform fashion, without partitioning it to 2GB of "application
memory" and 2 or 6GB of "other memory". Win2K Datacenter can use up to 32
GB.

Each process' 4 GB of virtual space is partitioned as 2 GB user mode space
and 2 GB of kernel mode space (you can optionally have it as 3 GB of user
mode space and 1 GB of kernel space, but it brings other unwanted
limitations to the system).

All of that physical memory (up to said limit) participate in
physical->virtual mapping. No memory is left behind. If on a Win2K AS with
8GB you have 4 apps with about 2 GB working set each, they will work without
thrashing the swap. In Win2K Pro, accordingly, total working set is limited,
of course, to 4 GB.
 
Abolutely clueless. Start reading "Operating Systems for Dummies".
Click to expand...

Start reading the microsoft documentation I pointed to which states
exactly what I describe below.

Which part of that do you not understand?
 
Once again: Win2K Pro and Server and WinXP physical memory limit is 4 GB
(not 2 GB).
Click to expand...

Once again. The physical limit for the win2k Pro and winXP OS is 4GB.
But that is NOT what your applications get.

Do a search on /3GB at the microsoft website. I'll help you:
http://www.microsoft.com/whdc/hwdev/platform/server/pae/paemem.mspx

A quote from that artikel:
++++++++++++++++++++
Windows XP Professional and Windows Server 2003 Memory Support. The
maximum amount of memory that can be supported on Windows XP
Professional and Windows Server 2003 is also 4 GB. However, Windows
Server 2003, Enterprise Edition supports 32 GB of physical RAM and
Windows Server 2003, Datacenter Edition supports 64 GB of physical RAM
using the PAE feature.

The virtual address space of processes and applications is still
limited to 2 GB unless the /3GB switch is used in the Boot.ini file.
When the physical RAM in the system exceeds 16 GB and the /3GB switch
is used, the operating system will ignore the additional RAM until the
/3GB switch is removed. This is because of the increased size of the
kernel required to support more Page Table Entries. The assumption is
made that the administrator would rather not lose the /3GB
functionality silently and automatically; therefore, this requires the
administrator to explicitly change this setting.

The /3GB switch allocates 3 GB of virtual address space to an
application that uses IMAGE_FILE_LARGE_ADDRESS_AWARE in the process
header. This switch allows applications to address 1 GB of additional
virtual address space above 2 GB.

The virtual address space of processes and applications is still
limited to 2 GB, unless the /3GB switch is used in the Boot.ini file.
The following example shows how to add the /3GB parameter in the
Boot.ini file to enable application memory tuning:
+++++++++++++++++++++

Which is exactly what I said all along.

Marc
 
People who continue after losing an argument are known as Trolls. We have a
low opinion of Trolls around here.

There is no Microsoft documentation that supports your claim "... windows
pro/windows server will use 2GB for all applications in total".
 
People who continue after losing an argument are known as Trolls. We have a
low opinion of Trolls around here.

There is no Microsoft documentation that supports your claim "... windows
pro/windows server will use 2GB for all applications in total".
Click to expand...

I have just posted a link in my other reply with a quote from
Microsoft stating exactly what I already told you.

Btw: I have a low opinion of people that just post clueless oneliners,
instead of joining a discussion and actually learning something.

Marc
 
I cannot help with your reading comprehension problems, you better see your
psychiatrist.

The rest of us have no problem reading what it says, 2/3GB per process
depending on the application.
 
Maybe this will resolve the question:

http://www.crucial.com/kb/answer.asp?qid=3743

Let's say you have Windows 2000 Advanced Server with 8GB and PAE
enabled. If Photoshop doesn't use AWE and the /3GB switch is not
used, then it each instance of it is restricted to 4GB of virtual
address space, of which only 2GB are usable by the application and 2GB
are reserved for system objects.

If you have multiple instances of Photoshop, then each instance gets
the same 2GB application-usable virtual address space. Because
Windows 2000 Advanced Server can support 8GB of physical memory, then
it should be able efficiently to map virtual memory pages throughout
all (or most) of that 8GB range, regardless of whether that virtual
memory page is allocated for the application or the system, with the
excess mapped to the paging file. I don't understand why this OS
would limit all application allocated pages to at most 2GB of the
physical memory, and page the rest out to the swap file. Only Windows
95 has a 2GB limitation. At least that is my understanding.

Anyway, most of these applications that use large amounts memory can
be configured to use a temporary directory in one way or another,
because the file system size limits are much higher. So, a RAM-based
NAS would benefit these applications, because it would be mounted as a
drive.

Shailesh
 
I have just posted a link in my other reply with a quote from
Microsoft stating exactly what I already told you.

Btw: I have a low opinion of people that just post clueless oneliners,
instead of joining a discussion and actually learning something.

Marc
Click to expand...



Now you see what I was dealing with in the past. This is why I just
killfiled the lot of them and ignore the them when they do get through.
Hell, who can argue with Microsoft since they wrote the software?





Rita
 
Now you see what I was dealing with in the past. This is why I just
killfiled the lot of them and ignore the them when they do get through.
Hell, who can argue with Microsoft since they wrote the software?
Click to expand...

Well, aparantly they can...., since this guy replied that he didn't
read that, even though Microsoft was very clear on the subject and it
clearly supports my posts.

Oh well, at least other people now know where they can get the correct
information and judge for themselves. That's good enough for me.

That these people cannot admit that they were wrong doesn't really
bother me.

Marc
 
Maybe this will resolve the question:

http://www.crucial.com/kb/answer.asp?qid=3743

Let's say you have Windows 2000 Advanced Server with 8GB and PAE
enabled. If Photoshop doesn't use AWE and the /3GB switch is not
used, then it each instance of it is restricted to 4GB of virtual
address space, of which only 2GB are usable by the application and 2GB
are reserved for system objects.

If you have multiple instances of Photoshop, then each instance gets
the same 2GB application-usable virtual address space. Because
Windows 2000 Advanced Server can support 8GB of physical memory, then
it should be able efficiently to map virtual memory pages throughout
all (or most) of that 8GB range, regardless of whether that virtual
memory page is allocated for the application or the system, with the
excess mapped to the paging file.
Click to expand...

This is all completely correct for win2k adv server.
(and precisely what I have also stated in all my posts, and what you
can see confirmed in the links from Microsoft I posted)

But the problem starts when you have Win2k Pro or win2k server. Those
two versions do not support PAE and the /3GB.

And therefore those two version cannot map the virtual memory pages
throughout all (or most) of that 8GB range.
I don't understand why this OS
would limit all application allocated pages to at most 2GB of the
physical memory, and page the rest out to the swap file.
Click to expand...

"This OS" doesn't do that because it is Win2k Adv Server and it
doesn't have the (articial) limitations built in Win2k Pro and Win2k
Server.
Only Windows
95 has a 2GB limitation. At least that is my understanding.
Click to expand...

As you can see in the link you provided, win2k Pro is not listed as
being PAE capable. And thus limited to 4GB RAM.
Anyway, most of these applications that use large amounts memory can
be configured to use a temporary directory in one way or another,
because the file system size limits are much higher. So, a RAM-based
NAS would benefit these applications, because it would be mounted as a
drive.
Click to expand...

That brings us back to the start of the discussion. When that RAM
based NAS is hardly faster then a local harddisk, there is little
performance gain for the money you spend.

Other solutions presented here, like the ramdisk on a pci card, are
perhaps more expensive, but the performance gain of that is far
larger.

When you have a application that really needs that much RAM, you most
likely also have a good business case for spending a bit more money on
a really effective solution.

Marc
 
Other solutions presented here, like the ramdisk on a pci card, are
perhaps more expensive, but the performance gain of that is far
larger.
Click to expand...

Great example for dealing with and removing disk I/O issues.
When you have a application that really needs that much RAM, you most
likely also have a good business case for spending a bit more money on
a really effective solution.
Click to expand...

This holds true with any improvement.

Rita
 
Take your meds Marcy. I read all you stupid posts, and Microsoft does not
support you at all.

As to you Rita, I seem you remember your little love spat with Rod Speed last
month. Now it's you and Marc.
 
Before, you seemed to claim it's limited to 2 GB (while I tried to tell you
that the limitation is quite higher):
 
You are correct. Marcy does not understand the difference between physical and
virtual memory.

Let's ignore Advanced Server for now. If you are running Win 2K/XP on a 4GB
machine with two instances of Photoshop, they each have a 2 (or 3 with /3GB)
user process space, and each can have almost 2GB resident pages. The bit they
can't use is in use by the kernel and services.
 
As to you Rita, I seem you remember your little love spat with Rod Speed
last
month. Now it's you and Marc.
Click to expand...

How dare you speak ill of your little sock puppet buddy when he is in such
an emotionally fragile state? Rod (Corncob) Speed has been doing really
well after he has been massaging his prostate with that turpentine soaked
corncob for the last month. He needs to be commended since he was able to
get through one solid month without his normal childish insults. And since
he is now a courteous contributor to this group instead of the vile piece of
human excrement he previously portrayed himself to be you are extremely
jealous. Needn't worry, I'll send you a freshly soaked corncob if you don't
want to share Rod's. If you ask Rod nicely he may even want to show you how
to use it. Eric, when you grow up you will thank me. Just remember that
the cob is your friend, use it hard and use it often. Don't forget to soak
it in turpentine first.



Rita
 
Before, you seemed to claim it's limited to 2 GB (while I tried to tell you
that the limitation is quite higher):
Click to expand...

You confuse two of my claims:
The OS is limited to 4GB.
The memory the OS has available for the applications is limited to
2GB.

You will see that also in the two quotes you made below. The first
quote is about the limit for the applications. The second is about the
limit for the OS.

Before we go further I feel I should inform you that I have run into
the 2BG and 4GB in real-life and thus that I am not speaking just from
theory here.
I have several servers with 4GB, where all applications combined could
not use more than 2GB. When I used /3GB they could use 3GB in total,
but they could never use the 4GB in the server. (no AWE support in the
applications)

But we should really be able to discuss this further and agree on what
happens. There is after all enough good documentation about it.

Let's take some quotes from the document you suggested yourself:
http://support.microsoft.com/default.aspx?scid=KB;en-us;283037

++++++++++++++++++
Typically, a process running under Windows 2000 or Windows Server 2003
can access up to 2 GB of memory address space (assuming the /3GB
switch was not used) with some of the memory being physical memory and
some being virtual memory. The more programs (and, therefore, more
processes) that run, the more memory you commit up to the full 2 GB of
address space.
++++++++++++++++++
Especially the last sentence is interesting. The more programs you run
the more memory you commit up to the full 2GB!!! of space.

If each process has it's own 2GB virtual space and the OS devided the
different programs virtual memory allocations into the 4GB limit of
the OS, then the above sentence would be wrong.

Unless I am mistaken you do not agree with that assesment, and claim
that the OS DOES devide the virtual memory allocatins into the 4GB
limit of the OS. So please tell me how I should read that sentence
from Microsoft. I cannot think of any other way to interpret it.

That sentence also says that the different applications share the same
2GB of space.
That's also something we couldn't agree on.

The article goes on with:
+++++++++++++++++++++
When this situation occurs, the paging process increases dramatically
and performance may be negatively impacted. The Windows 2000 and
Windows Server 2003 memory managers use PAE to provide more physical
memory to a program. This reduces the need to swap the memory of the
page file and results in increased performance. The program itself is
not aware of the actual memory size. All the memory management and
allocation of the PAE memory is handled by the memory manager
independently of the programs that run.
++++++++++++++++++++++
"When THIS situation occurs" points to the situation of the first
quote where the applications commit up to the full 2GB of space. At
that point the systems starts with swapping.

Let's take our photoshop example: 4 sessions using memory.
When I substitute that in the quotes I get the following:
The more photoshop sessions (and, therefore, more processes) that run,
the more memory you commit up to the full 2GB of address space.
When this situation occurs, the paging process increases dramatically
etc etc.

Do you agree with this? (or do you agree that the MS documents
suggests that this happens)

If you do not agree, please explain using where you think I went wrong
in the assesment above.

Marc
 
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