Re: System Cache

Either you were half asleep when that lesson was given or your teacher needs to go back to school! The whole notion of having the file system cache on the hard disc defeats the purpose of the file system cache, which is speeding up file access by bypassing slow disc access!

John

Manfred Senn wrote:

Hello Edwin,

thank you for replying. I will read this book.
I only wrote what I was teached in the training!

Manfred

"Edwin vMierlo" <EdwinvMierlo@xxxxxxxxxxxxxxxxxxxxxxxxx> schrieb im Newsbeitrag news:%23WeoEMSGHHA.1280@xxxxxxxxxxxxxxxxxxxxxxx

Manfred,

I need to jump in here

1) do not use the counter in Task Manager for referring to system cache,
unless you fully understand how this counter is constructed. I would like to
recommend reading chapter 7 of the book "Windows Internals" (comes with the
resource kit for server 2003)

2) your claims about "file system cache" on disk is complete RUBBISH. With
all respect, this is not true. There is no "file system cache" on disk... it
is in memory. Again same chapter, same book will explain.

With all respect, stop posting stuff about "file system cache" on disk.
I will now stop watching and responding to this thread.

Thank you,
Edwin.

"Manfred Senn" <msenn@xxxxxxxxxxxxx> wrote in message
news:eb0HF2QGHHA.1276@xxxxxxxxxxxxxxxxxxxxxxx

Hello John,

You can see the maximum size in Task Manager it is about 80% of the RAM.
As far as I know you cannot manipulate the location of the file system
cache.
It always lies on your default windows drive normally C:
And you cannot backup it, only when you use a image of the disk.

Again, it would be nice if anyone from Microsoft would tell us more about
this.

Manfred

"John John" <audetweld@xxxxxxxxxxx> schrieb im Newsbeitrag
news:eCIjXwJGHHA.1804@xxxxxxxxxxxxxxxxxxxxxxx

I know the difference between the pagefile and the system cache! I don't
dispute that it might be a problem in some circumstances! What I don't
understand is your initial statement: "Windows puts an area of the size

of

about 80% of the RAM on the local disk. This is the "file system cache"."
What is this deal about the file system cache being on a different file

on

the hard disc? Where does this information come from?

John

Manfred Senn wrote:


That is a big problem!?
I know this issues from a Windows 2003 Troubleshooting training, where
the trainer showed the increasing of the file system cache, while

copying

a large amount of files, and we discussed the disadvantages of this
problematic.
You can watch the Cache in Task Manager - Performance - Physical

Memory -

Systemcache.
You will see that Systemcache wont fill up to more than 80% of the size
of your RAM.

You wont find anything about that problematic in the internet.

Microsoft

doesn't want that this is public.

File system cache an pagefile are totally different things.
You can fix the size of the page file, and you can see the file.
Set your page file to zero, and you will see that it has nothing to do
with the Systemcache. Your system will work.

Again: There is no way to see or fix the size of the file system cache,
only by changing RAM.
Again: Registry hacks dont fix this problem for Windows 2003!!! (maybe
2003 R2 does it? Idont know)
That's the hard truth. Don't put too much RAM in your computer if you
dont really need it. It can be contraproductive.

I know a company in germany that radically reduced RAM in domain
controllers (256MB) and servers because of problems with replication

and

data synchronization.

I will contact the company and ask them to post details in the

internet.

Manfred

"John John" <audetweld@xxxxxxxxxxx> schrieb im Newsbeitrag
news:uTr8MZIGHHA.3464@xxxxxxxxxxxxxxxxxxxxxxx


I would be glad if you pointed us to an article about this business of
the file cache being on the hard disc. Lets not confuse the pagefile
with the file cache. I only know of one file cache and it is in an

area

of the RAM. Please provide further information for the disc file cache,

I

would like to find out what this is all about.

John

Manfred Senn wrote:



Yes, there is a cache in the memory too, and I think this works

together

with the file cache. I would be glad if anyone from Microsoft would
comment this ...

"John John" <audetweld@xxxxxxxxxxx> schrieb im Newsbeitrag
news:%23R3Wf27FHHA.1240@xxxxxxxxxxxxxxxxxxxxxxx



I thought that the File System Cache was an area of memory which held
files recently accessed on the hard drive? If the application then
needs to use the same file again or write to it, it is retrieved from
or written to the much faster memory cache instead of the disk. The
files are held or cached until flushed to the disk.

John

msenn@xxxxxx wrote:




Windows puts an area of the size of about 80% of the RAM on the

local

disk. This is the "file system cache". Windows doesn't show you this
file system cache, but you can imagine it as a large file normally

on

your Drive C. When you do large file copies to your disk, you can
monitor the increasing of the cache in the task manager. In this
moment
the copied files do not stay in the directory where you meant to

copy

them. They are in the file system cache. This can last a long time
until the file system cache is emptied an written to the real
location.
Microsoft knows that there are problems with the file system cache
when
you have machines with much RAM. Maybe when you backup a system and
the
file system cache is not empty there can be a loss of data. In large
domain environments, this can cause problems, if the file system

cache

is to big. There may be replication problems. To fix the problem

some

companies go the way and reduce the memory of domain controllers to
256MB RAM. Because then the file system cache is 80% of 256MB, and

the

problems are gone. There is no way to reduce the file system cache
manually (The only way is reducing RAM). You can find registry

hacks,

but they dont work.

Bob I schrieb:





No, IT'S YOU that doesn't understand, you haven't started giving it
anything in particular to do yet.

b11_ wrote:





You don't understand. After I boot the computer and reach the
desktop, there
is about 1000 mb of free memory which is much more than enough to
run games.
There is never a shortage of free memory!
_________________________________________________________________

"Sharon F" wrote:






On Tue, 7 Nov 2006 16:33:01 -0800, b11_ wrote:






System cache is in memory. It is not on the drive.

And as I said, this is a good thing. When your system needs to
cache to the
hard drive because the RAM is needed for other tasks, it will do
so. As it
stands now, your system is running optimally. No need to change
anything.

--
Sharon F
MS-MVP ~ Windows Shell/User








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