Swap space is an area of the hard disk that serves as an overflow when the computer memory is full. The memory used by inactive applications is partially written out to disk to make room for other applications and for the disk cache for active files.

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Can a VM swap to host main memory.?

While my developer machine has a lot of memory, my vmware VM is 32 bit only and needs some swap space. Can I make it to swap into the host memory? If so, is it possible to use compressed swap space ...
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How to migrate files on Linux from HDD to SSD on a VDS

I upgraded my Dedicated Server and I was having problems finding my SSD. I found out how to MOUNT my SSD. I now have my 100 GB HDD and now 20 GB HDD. [root@server /]# mount /dev/xvdb1 /ssd ...
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Swap bash script pins htop's memory usage

I deployed a hack to add swap space to a VPS that otherwise didn't allow me to use swapon to create a file. Prior to adding and executing the script, I followed the steps outlined here. and ...
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GNU/Linux swapping blocks system

I have used GNU/Linux on systems from 4 MB RAM to 512 GB RAM. When they start swapping, most of the time you can still log in and kill off the offending process - you just have to be 100-1000 times ...
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69 views

Something happened to Swap; it is not used by default

I always have to go to gparted and then turn my swap on. The swap space isn't used by default and if I turn the swap on, the swap is not used! How can I make the swap space be used by default at boot? ...
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Zswap, Zram, Zcache desktop usage scenarios

I've been trying to understand the difference in use cases for Zswap, Zram, and Zcache. Apologies in advance for the long/slightly sloppily worded question. I've done a bunch of googling, and I ...
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1answer
92 views

Copy of full swap file is empty

I use a swap file (/mnt/swap). The swap works right. I need to get an access to the data stored in. When it's full of data in some part (which I can see typing "free" in terminal), I copy the file to ...
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3answers
88 views

How to get data shown out of workspace or directly from application?

Because of some reason I had to use another web browser than my main which I use daily and I chose a small browser which I installed long time ago. This brower is called Dooble, version 0.07 ...
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292 views

Spike in swap utilisation without high swap rate

Every Saturday, for reasons unknown to me, one of my servers experiences a spike in swap utilisation. It's not necessarily a problem as there is plenty of free memory available, but I'd still like to ...
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Process Monitoring on Solaris

$ prstat -t NPROC USERNAME SWAP RSS MEMORY TIME CPU 164 oracle 5446M 5445M 8.3% 13:47:50 1.6% 52 root 576M 728M 1.1% 42:29:50 1.0% 1 noaccess 300M 273M 0.4% 0:20:54 0.0% ...
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Could the Kernel stack of a process be empty, when a process is swapped out to a disk?

I am just curious to know whether the Kernel stack could be empty when a process is swapped out to a disk or not?
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Can Linux “run out of RAM”?

I saw several posts around the web of people apparently complaining about a hosted VPS unexpectedly killing processes because they used too much RAM. How is this possible? I thought all modern OS' ...
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Copying large file causes excessive swap

On a mid-class CentOS 6.4/64 server with 32 GB RAM, 3 TB free disk space, operating as KVM hypervisor, I start copying a 200 GB file to a destination in the same local filesystem. In fact, this file ...
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2answers
100 views

Swap separation for multiple distributions [duplicate]

I have 3 Linux distributions on my machine (Ubuntu, Arch and Fedora). I allocated half the RAM size (3GB) as swap for each of them. (I have realized that having 3 distributions is not of much use to ...
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185 views

swap space allocation vs swaptotal

I created a Red Hat 9 virtual machine on VMware Workstion 9 by allocated the physical memory of 256MB. See pic. When installing Linux, I created the swap partition with a size of 256MB. See ...
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2answers
963 views

swapoff fails when overcommit_memory==2

I've disabled memory overcommitting by setting overcommit_memory=2. Now when I tried to swapoff, I get this error: swapoff: /dev/sda5: swapoff failed: Cannot allocate memory But I in fact have 0 ...
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Why is swappiness set to 60 by default?

I just read some stuff about swappiness on Linux. I don't understand why the default is set to 60. According to me this parameter should be set to 10 in order to reduce swap. Swap is on my hard ...
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218 views

slow Matlab on Ubuntu LTS and ZERO Swap

I was using Matlab2012 under Win7 and my algorithm was consuming a huge amount of memory though it was fast (80 seconds for one iteration). Now I am using Matlab2013 under Ubuntu 12.04 LTS and though ...
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What is the purpose of multiple swap files

During installation of most (if not all) distro's of linux, the hard drive is partitioned to include a swap partition by default. It is possible to change this behavior with swapon -p priority ...
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Does the order of partitions matter much?

I've just ran a test install of Arch on a separate computer, and now I'm ready to do the real thing on my main one. However, since the guide didn't explicitly recommend it, I did not install with a ...
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0answers
238 views

43 seconds to mount swap on /dev/mapper/cryptswap1

My Linux Mint takes longer than I would expect it to boot. Checking dmesg I see the following consecutive entries: [ 8.335668] Adding 9767484k swap on /dev/mapper/cryptswap1. Priority:-1 ...
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2answers
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What NOT to put on an SSD?

I bought an SSD and I am going to set up my desktop system with a completely fresh Linux installation. SSDs are known to be fast, but they have a disadvantage: The number of writes (per block?) is ...
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Can linux systems on multiple virtual machines share the same swap partition? [duplicate]

I'm trying to save some disk space between multiple systems and re-using the same swap partition (which seems to be fine). I'm now getting into multiple virtual machines and am thinking of a ...
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172 views

Can I remount as readonly if there's a swap image in use?

When am playing with my Android phone (CyanogenMod 10.1 with kernel 3.0.78), I found this: A script in /etc/init.d/99system.swap.sh It remount /system as rw, and creates an image file in ...
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165 views

can initramfs be paged out to swap disk?

I am using initramfs to boot Centos via PXE. The initramfs used memory is listed within the "cached" value in /proc/meminfo or via free. Since I need to calculate performance data, I need to know ...
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474 views

RAM size and SWAP size

I want to know why the swap partition have to more double size the RAM Size ? for example if the ram installed in machine 64 G.B , the swap have to be 128 G.B ?
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Linux: Total swap used = swap used by processes +?

So, I'm trying to do some investigation on where does swap use come from in a system with high swap usage: # free total used free shared buffers cached Mem: ...
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Where is the virtual memory stored on hard drive?

If a process wants to access a memory address that is not in physical memory, the OS outsources a page frame from physical memory to the hard drive for later use. Where on the hard drive is this data ...
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1answer
148 views

Arch installation and swap partition

to install Arch on a PC I have to make partition of the HDD boot swap / The swap is used by virtual memory, right? What's up if I make a too small or a too big swap partition? Could I have as ...
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1answer
506 views

Dual-booting Windows 7 and Mint 14 with “something else” option

I would like to do a dual boot of Windows 7 and Mint 14 on my Acer netbook which already has Windows 7 Pro 64-bit installed on an 1 TB hard drive. I have already shrunk the Windows 7 partition to ...
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2answers
530 views

swap partition and its laws

I remember for choice of swap partition, we should use (swap > 2xRAM) at least.Of course it deprecated , because max of computer's ram is very high. kernel support it. My question: i remember each ...
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2answers
469 views

Is it a bad idea to not have a swap partition on an embedded linux setup?

I have a small embedded linux kernel and file system created via buildroot that is installed onto a compact flash drive running on an x86 board. I am using an initramfs (due to power loss concerns) ...
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kswapd0 takes 99% to 100% CPU in RHEL 6.3

I have 5 systems on which I have just installed RHEL6. System configuration is CPU-i7 HDD-500 GB RAM-2 GB Swap- 4 GB I have installed the same software's and all the configuration as per ...
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How do I configure systemd to activate an encrypted swap file?

My previous question produced the commands to add an encrypted swap file: # One-time setup: fallocate -l 4G /root/swapfile.crypt chmod 600 /root/swapfile.crypt # On every boot: loop=$(losetup -f) ...
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How do I set up an encrypted swap file in Linux?

How do I set up an encrypted swap file (not partition) in Linux? Is it even possible? All the guides I've found talk about encrypted swap partitions, but I don't have a swap partition, and I'd ...
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506 views

Memory management, bias to swapping

I was having 768 MB RAM. In a general day MySQL was using 100-180 mb of RAM and MySQL was swapping 80-120 mb. I was having 50-60 mb free RAM. So I thought I should upgrade. Then I upgraded my RAM ...
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828 views

Which processes swaps memory

I can see swap's total, used, free etc. sizes from top command. But I can't figure out which process uses swap, is it possible to find out swap memory by process? I'm running CentOS 6.3.
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How can I open a file in VIM in readonly mode if it already has a swapfile?

When I use the command :e filename to open a file and this file is already opened by another vim instance, I get a prompt asking me if I want to open the file in read-only mode, edit anyway, recover, ...
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3k views

Create swap partition after install

I already have parititon contain data under lvm enviroment with centos 5.8 output of fdisk -l root@server [~]# fdisk -l Disk /dev/sda: 1000.2 GB, 1000204886016 bytes 255 heads, 63 sectors/track, ...
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817 views

What does m represents in VIRT column using TOP command

When we run top command it shows all the processes information. But under VIRT column there is m written against some values what does that m represents, is it MB . If yes then why it is only showing ...
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Swap usage too high?

I have a debian sid box, freshly installed about a month ago, with no desktop apps running at the moment. Any command I try to run (via ssh) makes the hard disk work very hard. The system worked ...
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2answers
837 views

Linux (3.4) SSD swap partition usage causes extreme latency - how to eliminate?

I'm running on 4G RAM with an extra 6G swap partition, SSD is a pretty decent SAMSUNG MZMPA128HMFU model. System responds very well to workloads when things stay in RAM, but as soon as things reach ...
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256 views

Turn on Swap after resize /

I resized with lvresize the swap from 4 to 2G and can't turn it on. swapon /dev/VolGroup/lv_swap swapon: /dev/VolGroup/lv_swap: swapon failed: Invalid argument lvdisplay /dev/VolGroup/lv_swap ...
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2answers
1k views

Does swap need to be on a contiguous LVM logical volume

I am setting up a machine to run a number of virtual machines. I am using a single HDD with a boot partition and an LVM partition. I read on the Arch wiki that logcial volumes which will be used for ...
4
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1answer
470 views

How to stop waking all attached drives on reboot / deactivating swap?

A fresh install of Debian 6.0.6 for a system has 13 SATA drives attached. 12 refurbished WD-10EARS drives are yet unpartitioned. 1 WD1500BLFS drive is configured for OS and swap. Swap partition is ...
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zram swap instability

I use Mint 13 Maya with mainline kernel 3.6.3 for Ubuntu Quantal on my Asus P53E Notebook. I use zram swap that comes with the package zram-config. I've noticed that using it the system to hangs at ...
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What about no swap?

I have a netbook with a very slow (especially on writes) SSD, would it be a good idea to go without swap? The way I see it is that code and unmodified pages will still be swapped (re-read) but I won't ...
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Drop_caches doesn't drop caches?

Sometimes I see my swap file is a bit bigger then usual. I tried sync && echo 3 > /proc/sys/vm/drop_caches to no avail. But when I tried swapoff -a it takes a bit longer but the swap file ...
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435 views

Swap space not used

I recently installed Debian 6.0.6. Here are the machine's states: CPU - AMD XP 3000+ RAM - 1 Gig HDD - IDE 80 Gig I primarily use this machine for developing toy personal projects. When I run ...
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2k views

Tmpfs only with RAM

How to be sure that a tmpfs filesystem can only deal with physical and it's not using a swap partition on disk ? Since i have a slow HDD and a fast RAM i would like, at least, giving higher priority ...