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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How to obtain counters for swap-in/swap-out on Linux?

I'm trying to obtain counters for swap-in/swap-out activity on CentOS 6. The intention is to feed raw data into RRDtool to generate graphs, and use it to generate alerts. I've had a look at common ...
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mkswap complains that partition is misalilgned (LVM on RAID-0)

I have a RAID-0 setup on two identical hard disks (same brand and model). The partition table is identical on both (I have cloned it). However, /dev/md0 occupies only part of the disks, because I had ...
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How can I check if swap is active from the command line?

How can I check if swap is active, and which swap devices are set up, on the command line?
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Can I deny use of swap space to a specific process (and have it just get killed)?

While developing some software, a program under test sometimes eats all the memory, then proceeds to yomp into the swap space and start thrashing the disk, leading to a predictable drop in ...
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Unable to activate new encrypted swap partition

First off, I did not reboot and would not like to, it's a server. It is running Debian Jessie 8.4 with kernel 3.16.0-4-amd64. I followed these steps: apt-get install cryptsetup -> no problem ...
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Linux using whole swap, becoming unresponsive while there is plenty of free RAM

I am experiencing a weird issue lately: Sometimes (I cannot reproduce it on purpose), my system is using all its swap, despite there being more than enough free RAM. If this happens, the systems then ...
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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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set swap space to 0 on RHEL for testing

I have tried to change the swappiness to 100, and used the malloc() code in order to set the swap to 0 on my rhel system But this not seem to be helpful . The system memory allocation looks like this ...
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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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Get swap memory info where swapinfo not available

I have HP-UX box. I need to write shell script to see the swap memory. Unfortunately. The box don't have swapinfo command. Is there any alternative way to see the swap usage percentage? Please note ...
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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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Ext4 corrupted and unrecoverable after LVM resizing + power failure

I have a completely standard, single hard drive Fedora 23 desktop. The dual-boot installer set up the Linux partition as LVM, with root, swap and home logical volumes; root and home were both ext4. ...
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39 views

Vim saved file not updating on webpage

I am attempting to update an HTML file on my server, but when I do so it doesn't appear to be updating, but rather, serves an old copy instead. I went through the usual process of pressing :w and ...
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630 views

Swap appears to not be in use

(I am currently using Ubuntu 14.04 LTS, GNOME environment) tl;dr How can I force more memory swapping (swappiness already at 100)? I have recently been experiencing a lot of system freezes/crashes. ...
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49 views

Keep a process in RAM (prevent it from swapping)

I want to keep a process in RAM. It should never go into swap. Is this possible? The process is a Java program. I'm running CentoS 7.
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how does systemd activate encrypted swap file on alternate partition?

I have 2 partitions: / and /data. My swap file is encrypted at /data/swap. So /etc/crypttab looks like: root_crypt UUID=6666 none luks swap /data/swap /dev/urandom swap And /etc/fstab looks like ...
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How does Linux manage “simultaneous” writes to swap/disk partitions in virtual memory?

I'm currently working on an educational operating system called Pintos. While implementing virtual memory, one of the issues that I'm having is writing data to swap in a page fault that happened while ...
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Silent disk errors and reliability of Linux swap

My understanding is that hard drives and SSDs implement some basic error correction inside the drive, and most RAID configurations e.g. mdadm will depend on this to decide when a drive has failed to ...
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Making a swap partition using lvm

When we make a swap using a regular physical drive, we just use fdisk and make a partition with type swap, using the swap code for that partition, followed by mkswap and swapon commands. But what ...
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Cleaning swap space while running

I have a theoretical question, What would happen if I clean up all the swap space while running, Would the operating system crash because of page faults that would happen in the kernel?
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How to set per process swapiness for linux?

/proc/sys/vm/swappiness is nice, but I want a knob that is per process like /proc/$PID/oom_adj. So that I can make certain processes less likely than others to have any of their pages swapped out. ...
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Machine freezes once it hits swap space under heavy load

I encountered several crashes of my machine. Meanwhile, I can reproduce it when I start a program that fills up all memory. Once the system starts writing to the swap file, the system freezes and I ...
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Log from oom killer

I'm running a virtual machine at a provider where you pay for everything you use (CPU, memory, disk IO, bandwidth, etc). Currently my machine has 512MB ram and 1GB swap area. The kernel version is ...
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How do I increase the maximum swap space on Mac OS X? [closed]

On Mac OS X Yosemite 10.10.5, when I try to run a calculation that needs to allocate and use 128 GB of memory (it is a command line program written in C), the kernel kills my process with extreme ...
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swap goes the second drive, how can I return it to normal from command line?

The following is my plan for partition of CentOS 6.7. I have two disks with A for system and files, B totally for backup. But, after installation, I log in using ssh root. Here is what I see: ...
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Setting up encrypted swap in LMDE (debian)

I want to use a swap drive that is encrypted by a random key on boot. I'm not sure if I am doing it safely, though. I currently have /etc/crypttab based off of the example on arch wiki. Unlike their ...
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35 views

-/+ buffers/cache & Swap

When should the usage of swap get started? or How do I know that my swap is being used? At least some times if not always, considering the default swappiness of 60 Also, why does free offer to omit ...
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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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vm.swappines parameter influence on system without swap partition

I run across following definition of vm.swappines: The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk. So, if I have ...
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Crash with input/out error and swap unmounting [duplicate]

I am looking for hints on this problem. I've searched around, but can't find something exactly similar. I am running Debian 8 stable, updated, very minimal install (i3wm, small number of apps ...
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How to configure swappiness in Linux Memory Management?

The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk,what is the default setting and how to configure that to improve overall ...
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659 views

8G RAM and SSD - how big should the swap be?

I have a computer with 8G RAM and a 128G SSD. I don't plan hibernating. What swap size would you recommend? Would you change any swappiness? In the nearest future I'll compile programs (or even ...
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why we need ram if we having swap memory? [closed]

In Linux we have a swap memory right. the system will use swap memory if ram memory is full.then what is require of RAM we can use directly swap memory.
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Wear leveling of SD card because of swap file in embedded linux

I need to enable a swap file on my embedded linux product. The problem is that the file is located on an SD card. At the moment I'm using 15MB swap and about 120MB RAM because of temporary increases ...
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Recover from faking /proc/meminfo

So, without really thinking too much, I ran this script: #!/bin/bash SWAP="${1:-512}" NEW="$[SWAP*1024]"; TEMP="${NEW//?/ }"; OLD="${TEMP:1}0" sed "/^Swap\(Total\|Free\):/s,$OLD,$NEW," /proc/meminfo ...
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hibernation and swap partitions on ssd/hdd

I'm quite a beginner in Linux and I've got some problem to decide: I've got a laptop with two disks - 1TB HDD and 256 SSD, and 12GB RAM and I want to install debian on SSD. I used hibernation a ...
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Real-time monitoring of changes in swap use (per process)

I'm looking for a way to observe which processes in my system are consuming an increasing amount of swap over time. The following function generates a list of swap user per process : sbp(){ grep ...
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125 views

Pulling all of a process's swapped memory out of swap

How would one go about quickly pulling all of a process's swapped memory out of swap without writing to disk? The context on this issue is trivial, as the systemic issue necessitating the question ...
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105 views

Free up swap space all at once after swap event

I use my Linux box for a lot of computational work, and sometimes a particular computation eats a lot of RAM. When I'm done, I end up with a bunch of swap used and a bunch of free memory, and if I go ...
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Why does /proc/*/status not account for all swap used on a system?

I have a system that has been swapping recently and am unable to account for all swap that is shown as in use by tools like 'free' or 'top'. Specifically, I can account for 19GB of 28GB swap used ...
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117 views

Encrypted filesystems with swap partitions

A common error that happens with Ubuntu, though not Ubuntu in particular is the options of being able to encrypt the file system at installation time which creates an encrypted swap partition with ...
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65 views

Swap output in last x minutes

Is there any command or script to give o/p as " swap used in last 10 minutes is x" ? I wished to use that out put for my nagios monitoring.. I have used SAR in my below script and is trying to run on ...
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46 views

Can I mark _current_ memory contents as non swappable?

Background: in my linux (ubuntu) workstation, I want to run some experiments that allocate more memory than the physical RAM while I do other 'normal' stuff in the GUI. Problem: I have plenty of ...
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I need to take the output of command and make it the name of a file using a script [duplicate]

I am working on a way to integrate our Linux machines into our SCCM Reports. One of the things we would like to do is verify the swap size on the machines. I know that I can get the swap amount on ...
3
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2answers
101 views

Swap: Better to create a dedicated swap partition or to create a swap file?

is there a rationale when to create a dedicated swap partition vs. creating a swap file, for example like /tmp/swap? In my certain case, memory is kind of low (1GB), disk space on a SSD is pretty ...
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how to make swap permanent in vm?

I create the ubuntu vm by vagrant. I want to add the swap to vm. the steps: mkdir /swapfile cd /swapfile sudo dd if=/dev/zero of=swap bs=1024 count=2000000 sudo mkswap -f swap sudo swapon swap add ...
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Creating a sparse (automatically expanding and contracting) swap file with hole-punching support

I have this crazy idea, and want to know the pitfalls of such an approach (or whether it can even work with no deadlocks.. etc). The goal is to create an automatically expanding and contracting ...
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Extending swap on Centos

I recently created a swap file on my centos 6 based VPS using this guide. Now I wanted to extend this swap and I was reading through this guide. However, I think I've created a swap file than a ...
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Can't delete a swap partition, says that it's mounted while swapon says it's not?

I have a swap partition mounted on /dev/sda6 Linux Mint 17.2/Windows 10 dual boot. Am using HP 2000 notebook PC with 4GB RAM. When I installed Linux Mint I created a swap partition which as it happens ...
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When hibernating : “PM: Swap header not found”

I've already seen Debian hibernate problem PM: Swap header not found, but the difference is that it's not a file swap but actually a swap partition. I'm on Ubuntu 15.10. My swap partition: $ ...