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Questions tagged [virtual-memory]

It is an extension of memory address space which is logically appended to the physical memory of a computer by the Memory Management Unit (MMU) of its processor. It is normally realized in operating systems by utilizing free disk space to implement such memory extension and may also be referred to as swap-file or page-file.

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Meaning of the buffers/cache line in the output of free

Why does my server show total used free shared buffers cached Mem: 12286456 11715372 571084 0 81912 6545228 -/+ buffers/cache: 5088232 7198224 Swap: 24571408 54528 24516880 I have no idea on…
Muahmmad Zeeshan
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Caching/preloading files on Linux into RAM

I have a rather old server that has 4GB of RAM and it is pretty much serving the same files all day, but it is doing so from the hard drive while 3GBs of RAM are "free". Anyone who has ever tried running a ram-drive can witness that It's awesome in…
Andrioid
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swap partition vs file for performance?

What is better for performance? A partition closer to the inside of the disk will have slower access times, and we must wait for the drive to switch between the OS and swap partitions. On the other hand, a swap partition bypasses all of the…
Bill Gray
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In Linux, what is the difference between "buffers" and "cache" reported by the free command?

This is an old question that I've seen from time to time. My understanding of it is rather limited (having read about the differences a long time ago, but the factoid(s) involved never really stuck). As I understand it, Buffers Are used by…
Avery Payne
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How do I tell what process is causing kswapd to be in use?

I see kswapd using 100% CPU... how can I tell on which process's behalf kswapd is being used so much?
Deshawn
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Difference Between Private Memory Limit and Virtual Memory Limit in IIS

I want to set the max limit on the physical memory an application can use in IIS 7. Should I set a limit on Private Memory Limit or Virtual Memory Limit? Can some one point me to documentation of all settings in IIS 7
kishore
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What is "a lot" of Page Faults?

I am monitoring the memory object in Windows 2k8, and am tracking the Page Faults/sec counter. Is there any threshold to determining what is an excessive amount of page faults? Or should I be more concerned with a sustained, high, amount of page…
MattUebel
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How to limit the memory used by an application in IIS?

The IIS worker processes are taking lot of memory on our servers. I want to limit the memory each application can use. I am confused whether I should set a limit on Virtual Memory Limit, or Private Memory Limit. Each application in our IIS is on its…
kishore
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Constantly Increasing swap size in Linux and Swap space not being reclaimed?

I have a 8GB RAM linux box on which 4 tomcat servers are running. One of the them is set to 3000MB memory(jvm -Xms and -Xmx setting) and others are set to 1500MB. The swap partition is also set to 8Gigs. When I start these servers, the swap file…
Zenil
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Ballooning occuring on SQL server

From what I understand ballooning should occur only when the host begins to run out of physical memory, somewhere above 90% usage. I have an SQL server running in a three node cluster (64 GB RAM in each host) and it has been assigned 8 GB of RAM as…
user35213
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How to sort top result on virtual memory on Redhat Linux?

There is an interactive key "M" to sort by memory, which seems to be sorting on resident memory. Is there a way to sort on virtual memory? I happen to be working on Redhat Linux, but the question is not specific to this distribution.
timeon
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Understanding virtual memory usage > swap + physical on Linux

I have a process that is reporting in 'top' that it has 6GB of resident memory and 70GB of virtual memory allocated. The strange thing is that this particular server only has 8GB physical and 35GB of swap space available. From the 'top' manual: …
Belly
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How do you measure the memory footprint of a set of forked processes?

Say I've got a process using 200MB of memory, and it fork()s: python -c "import os; data='x'*200000000; os.fork(); raw_input()" Programs like 'top' will show each process using 200MB, with very little SHRd memory, so it appears as if the processes…
Dustin Boswell
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Linux OOM disk I/O. Also: swap, what is it good for?

I'm having problems with the OOM killer on one of my Linux (2.6.37) installs. The computer has 4GB of memory which I sometimes utilize fully. In those cases, I expect the OOM handler to come in and do its job by killing a process or two. Instead…
extramuros
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What are the exact conditions based on which Linux swaps process(s) memory from RAM to a swap file?

My server has 8Gigs of RAM and 8Gigs configured for swap file. I have memory intensive apps running. These apps have peak loads during which we find swap usage increase. Approximately 1 GIG of swap is used. I have another server with 4Gigs of RAM…
Zenil
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