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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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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Mysql / swap space full

I have MySQL Ver 14.12 Distrib 5.0.45 server running on Multiflex Intel Blade having 8G of RAM & 8 x Intel(R) Xeon(R) CPU E5410 @ 2.33GHz. The problems I am facing are: For the last 3-4 days ...
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Which parts of Memory can Swap Support

For this question, "swap" does not include RAM and only refers to the configured space on the disk. According to, http://www.ualberta.ca/CNS/RESEARCH/LinuxClusters/mem.html, a program's memory usage ...
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558 views

Why adding swap space is the slowest part of the booting process? [closed]

I can see that adding Swap space is the slowest part of the booting process. Why? I actually have ~4GB for swap and 2GB RAM memory. dione@saturno:~$ dmesg | grep -C 4 swap [ 2.179979] input: ...
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216 views

Swap on video ram in a VM

I have a very small VM running in a cloud with only 512 MB ram. I read, it is possible to use the video card as swap as descriped here: Graphics cards contain a lot of very fast RAM, typically ...
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93 views

specific swap partitions for multiple debian instances in a single computer

I'm trying to setup a computer with three debian instances (wheezy, jessie and sid), I've created / and swap partitions for each debian instance, during the installation I did specify which swap ...
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2k 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 to disable swap file after install or during Kubuntu install?

My computer has more than 64KB of RAM (8GB), if I run out of memory I want things to crash so I know I'm out of RAM so I'll buy some instead of say wandering why my computer is running slowly when I ...
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511 views

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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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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What is excessive swapping

This post led me to ask that question. Cache contention On a large site, if you are using MyISAM, contention occurs in the database tables when the cache is forced to clear after a node ...
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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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163 views

How low can I go on RAM?

I have some old PCs runnning on my business. And by old I mean PENTIUM-3 800 MHZ and AMD DURON 950 MHZ, with 256MB RAM. They are running my business software today on Windows XP. I want to run Linux ...
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265 views

Is there way to force Linux to unswap when there is low CPU usage?

After working more than 1 day on my machine swap becomes about 1GB. Some of my panel plugins go to swap so they become laggy. Moreover system doesn't unswap until I make it to do it swapoff -all;...
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184 views

Will SSD swap improve performance?

I am wondering if i have only 4GB ram and somehow(virtualbox,browser) isn't enough and i cannot proceed to upgrade(due to ultrabook and soldered memory) will swap held in SSD help the overall ...
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3k views

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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160 views

Does asynchronous disk IO affect swap usage?

I have a server application requiring usage of huge memory but can take little time. I therefore thought it should be economical to run it with a big swap and normal ram. I was reading about serving ...
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244 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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732 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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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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Debian hibernate problem PM: Swap header not found

I have Debian 6 2.6.32-5-amd64 on netbook. With pm-utils Sleep works but hibernate fails with error: PM: Swap header not found!. Swap was enabled using ubuntu tutorial after installation - this is ...
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627 views

Is there a way to kick kswapd and make it swap out pages?

Even though I have set swappiness to 100 and enabled swap, nothing is being swapped out. This is probably because I don't have high memory pressure at the moment. For testing purposes though, I want ...
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Can lower swappiness speed up wake-up from hibernate?

Does anyone use swap? what is your swapiness value? Mine are 60 $ cat /proc/sys/vm/swappiness I use hibernation. It worked but slow to load when wake-up.. If I tune swappiness from 60 to 10. Does ...
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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 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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Fixing fstab after reformatting swap

I just made a small mistake and reformatted my swap partition. It's still formatted as a swap partition - I was fortunate not to touch anything more important. However, I notice that the uuid has ...
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198 views

On page fault, how does Unix determine if the faulting address is in swap space?

When a page fault occurs for a virtual address for any process how does the linux/unix operating system determine whether that page (of that virtual address) was swapped previously present in memory ...
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553 views

Is it safe to delete all swap partitions?

More explicitly: If it safe to shutdown a system, boot from a live cd, delete all disk swap partitions, and boot the system? This is in follow up to How to safely turn off swap permanently? (on ...
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VGEXTEND: How to avoid wiping a swap signature in /dev/sda3?

The problem: [root@195623 ~]# vgs VG #PV #LV #SN Attr VSize VFree fedora_195623 1 3 0 wz--n- 9,50g 0 [root@195623 ~]# vgextend fedora_195623 /dev/sda3 WARNING: swap ...
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302 views

Calculating RAM/Swap Space Requirements [duplicate]

I have been developing a MySQL database that makes some use of BLObs. This has now been transferred on to a virtual machine (VM) in preparation for going fully into the 'cloud'. However some of the ...
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443 views

OpenBSD runs out of memory, while not using swap space

I'm working with a fresh install of OpenBSD (5.6 amd64). I'm attempting to build Boost libraries, and quite a few compilations are failing with cc1plus running out of memory errors. I've read ...
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Fastest and Safest way to increase Swap Space on Scientific Linux

Memory Swap Ratio Company System Today, a monitoring system indicated that one of the systems in the company has run out of memory. Executing htop on this system indicated that the Memory was nearly ...
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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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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 to re-enable hibernate in Kubuntu 11.10?

After making some changes to my swap space, namely deleting and recreating swap space, my Kubuntu 11.10 has lost hibernate functionality. Although the button has returned, hibernating only appears to ...
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24 views

Use SWAP as disk cache in Linux

I am using different kind of disks on my server. Is it possible to use faster disk as SWAP and ask Linux to use it as Disk cache As I understand Linux use SWAP only for application data not disk ...
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31 views

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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91 views

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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28 views

What happens if my RAID fails while the swap is on it?

Today I removed swap from the system drive on my Debian. And created a swapfile on md0. So, I have a RAID1 array for data and a swapfile (the only swapfile). The system with boot partition is on ...
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53 views

Cached Memory but swap is being used [duplicate]

I've got a VM with 16gb of memory and recently it's been using some of the swap space. At first I thought this was because it was using all the memory but then I read some articles about the Cached ...
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126 views

How to add 100MB of swap space as a logical volume in CentOS?

I need to add 100MB of swap space to my machine. I was trying to use a logical volume. # lvcreate –name lv_swap2 –size 100M vg # mkswap /dev/vg/lv_swap2 # swapon /dev/vg/lv_swap2 # vi /etc/fstab /dev/...
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108 views

SWAP write protection on SSD

When using SWAP on an SSD, does the filesystem offer any write-cycle protection? i.e. randomizing or otherwise managing writes to avoid "flash wear-out" since modern SSDs are generally rated in the ...
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105 views

How are the values represented with the “free” command

I am interested in the totals of the 3 lines. Specifcally, if the "used" values can be counted as what's going on in real time, or if that's just a running total since the OS was started? How does ...
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68 views

How do I know I should turn swappiness down?

I have 5.5 GiB memory, using 2.8 GiB (~50%), but my swap is using 1.9 GiB of 5.6 GiB (~33%). My computer operates okay but is sluggish at times. So is this a high amount of swap usage or completely ...
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465 views

how partition for OpenSuSE dual-boot

Currently I'm running Ubuntu 14.10 and have quite a bit of free space on this disc: thufir@doge:~$ thufir@doge:~$ sudo fdisk -l Disk /dev/sda: 465.8 GiB, 500107862016 bytes, 976773168 sectors Units:...
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When the RAM is used up, what will happen?

When I ran ImageMagick's convert to convert and combine image files into a pdf file, it will create 10GB temporary dirs and files in /tmp. I am not sure if it did that all the time, or because my ...
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How to enable swap accounting for memory cgroup in Archlinux?

On my Archlinux box I want to limit some applications to a smaller amount of memory using cgroups. Since I use swap, I need to account memory+swap. How can I enable swap accounting?
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Allocation of Swap in 64 bit UBUNTU 13.04

I have 256GB ssd drive, 32GB DDR RAM, and 1TB HDD. What is the maximum limit of Swap memory that can be set in SSD?
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Is zswap eligible to reduce swap IO?

Does zswap compress pages, that are written to the swap device? Is it eligible to reduce swap IO?
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free / top difference. Does free show virtual memory?

free -m shows me the following in my system: total used free shared buffers cached Mem: 3954 3842 111 0 248 2585 -/+ ...