Mistery with Physical Memory consumption

I have a mistery memory consumption with one of my servers.  The server ihas 32GB RAM and normally gets 85% used.  Sometimes goes up to 99% and then down to 75% and climbs up again.  
If I combine all the Memory in the Task Manger processes I can maybe get 1GB in used.  However, the total shows 32GB and Cached 28GB and free only 377MB in Performance Tab.
Can someone help me here?  This is a real mistery for me why so much mamory is cached.  I attached a screenshot.
taskmgr.jpg
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Tiras25Asked:
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LMiller7Connect With a Mentor Commented:
What is the server running?
In a file server this would be typical behavior. You have to understand that server memory usage patterns are very different from a workstation. A file server exists to share files with it's clients and for this you want a large file cache. Data that is in the cache does not have to be read from the disk and this improves file sharing performance considerably. In a file server this will typically be the biggest user of memory. The memory manager will keep process memory usage low because nobody cares about application performance on a file server.

In a workstation this usage is reversed. Here application performance is paramount and file caching is of secondary importance. The memory manager will keep process memory usage high and trim the file cache to optimize performance where it matters.

In both cases you want free memory to be low. Free memory is wasted memory and should be kept to a minimum.

Also be aware that what is labeled "Page File" isn't really pagefile usage at all. This is actually the commit charge which is something quite different. It might be considered potential pagefile usage. There is nothing in Task Manager that will show actual pagefile usage and it really isn't that important.

The pagefile appears to be about 32 GB in size which would be the default configuration. It may be larger than needed but this will cause no problems. Unless you have disk space issues you will accomplish nothing by changing this.

Are you experiencing a problem or just wishing to understand this behavior?
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Thomas Zucker-ScharffSystems AnalystCommented:
Why do you have such a large paging file?  With that amount of RAM, according to MS specs you don't really need a paging file.  Probably on a server you'd rather have one - but remember it uses disk space as a RAM disk thus slowing down everything.

I don't see The cost listed here.  I think it's on another tab, but I'm not sure because I no longer use the built-in process monitor.  I use Process Monitor from windows/sysinternals instead (try it).
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Tiras25Author Commented:
Besides the paging file.  Why does the system use that much RAM?  

The Cost? What do you mean?  What is that?  
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Tiras25Author Commented:
Thank you for the explanation.  The high memory usage is also a mistery for me.  I do not see any high usage in the Task Manager processes memory.  But overall it's like 85-95% usage.  The server is just for a file sharing.
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LMiller7Connect With a Mentor Commented:
Adding up the memory usage of processes rarely provides meaningful results and this is particularly true on a file server where the file cache will be the big memory user. This is as it should be. On a file server that is what memory is for. Everything else is secondary.

In a file server you want as much memory as possible in the file cache. Why have 32 GB RAM and have a large portion sitting idle?

There is no mystery here.
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Tiras25Author Commented:
Okay got your point thank you!  Follow up question then. Does it make sense to monitor memory usage at all? Like we have monitors that alert us when over 95% used.
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LMiller7Connect With a Mentor Commented:
It is probably worth keeping if you don't have too many false alarms. It could warn you of a problem, such as a process memory leak. It is quite apparent from your description that that is not the case here. But you have to properly interpret the Task Manager display. Not all cases of high memory usage indicate a problem.
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oldstone00Commented:
It is probably SQL. Can you post a screen shot of processes tab and sort it by the memory? I know SQL will use all your memory unless you limit it in the database settings.
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LMiller7Commented:
SQL wasn't mentioned in any post. If SQL was running that would change the numbers considerably.
Memory usage by SQL will not show up in the file cache and most of it won't be in the process list either. The majority of SQL memory usage wouldn't be accounted for in Task Manager at all except in the total used.
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Tiras25Author Commented:
No SQL there.
procs.jpg
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Tiras25Author Commented:
LMiller7, BTW you mentioned >>In a workstation this usage is reversed. Here application performance is paramount and file caching is of secondary importance.>>
On my server under Performance Option adjust for best performance of:Background Services instead of Programs. Is that OK for a File Server?
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LMiller7Commented:
Yes.
That setting is the default and best for a file server. In a file server you really don't care about application performance. You want to optimize performance for sharing files on the network which is what a file server is for.
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Tiras25Author Commented:
Got it, thank  you!
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Tiras25Author Commented:
Hi LMiller7, and I look into this again, and the problem is that it’s consumed more resources than the server has and it’s become unstable.  Is there any way to specify that file caching can consume up to 90% of available resources and no more?
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LMiller7Commented:
I don't know of any method of limiting cache memory usage. This is managed by the memory manager and it generally does a very good job.

I see that there are two instances of java.exe running, together consuming more than 1 GB RAM for the private working set alone. This is not the full memory usage of these processes. Why is jave running at all if this is just a file server? Also, why is IE running? The amount of memory consumed is minor but that is hardly the point.

 
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Tiras25Author Commented:
I think I found someting and looks MS confirmed this is a problem.  Let me know what you think about this.

http://kbalertz.com/976618/experience-performance-issues-applications-services-system-cache-consumes-physical.aspx

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LMiller7Connect With a Mentor Commented:
That makes sense.
The default behavior works well for a file server. But if there are other processes that require substantial memory then this can be a problem. It appears that this system is more than a just file server.
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