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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Diagnose high swap usage on AIX

Which would be the best approach to diagnose high SWAP usage on an IBM AIX 6.3 machine? I've already tried with lsps -a and lslv. But also I'm looking for a strong scenario, like using topas. Any ...
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Why adding swap space is the slowest part of the booting process? [closed]

I'm not having performance problems, but just running dmesg command, 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 ...
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Why do I need mkswap if swap space has been created via fdisk?

I created a partition called /dev/sda3 as a swap partition, and changed the ID to 82 (Linux Swap) via fdisk. If this partition was recognized as a swap partition (seen in the output of fdisk -l and ...
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What's the pros and cons of disabling the swap partition if the RAM is large enough? [duplicate]

My computer has 16GB RAM and 1TB SSD. So I think the swap partition is not needful. What's the pros and cons of disabling the swap partition if the RAM is large enough? Is it recommended to disable ...
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Luks Partition Mounting After Removing From fstab

I have 3 encrypted partitions, one for /, one for /home, and one for swap. It seemed silly to me to type in my password 3 times, so I replaced the swap partition with a swap file on the encrypted ...
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swappiness and RAM usage

Been going through this topic - http://askubuntu.com/questions/157793/why-is-swap-being-used-even-though-i-have-plenty-of-free-ram. Turned down swappiness to 10 and then to 0 but my installation is ...
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Is swap an anachronism?

I've used unix for quite a while, and for the last couple years I've felt like swap is an anachronism, but I'd be curious what other folks think. My argument is roughly this (assuming no global ...
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Why use swap when there is more than enough free space in RAM?

Using swap space instead of RAM can drastically slow down a PC. So why, when I have more than enough RAM available, does my Linux system (Arch) use the swap? Checkout my conky output below: Also, ...
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full disk encryption (including swap, possibly plausible deniability as well)

I'm looking for a method to encrypt my laptop including the swap partition. I also read trough older similar questions but mostly the answer included just a what not much of a how. (Currently I'm ...
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What happens when a tmpfs is full and no swap space is available?

Let's say I have a setup with 16 GB of physical RAM, A tmpfs of max. 8 GB containing a file with 5 GB and A swap sized 4 GB. If I'd try to, e.g., create a copy of the 5 GB file on the tmpfs, what ...
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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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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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Is there anything in RHEL 6.5 that would affect I/O speed for something <24K vs >24K?

Generally, transactions for my app of setting and getting data internally are measured in a couple of millis. However, over 24K in size, that time can jump to just over 100 millis. Is there anything ...
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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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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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How to make files inside TMPFS more likely to swap

I'm using tmpfs for my /tmp directory. How can I make the computer decide to swap out the files inside the /tmp before swapping out anything that is being used by applications? Basically the files ...
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What does the vm.swappiness parameter really control?

Per the kernel documentation: This control is used to define how aggressive the kernel will swap memory pages. Higher values will increase aggressiveness, lower values decrease the amount of swap. ...
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How much RAM needed for preventing use swap?

At my system always available some "Free" and "Inactive" memory, but sometimes system move couple megabytes to swap. Per night it maybe around 100MB, but for a few days in swap could be more than ...
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Why is my swap not being activated automatically via fstab?

I've got a Linux embedded system that I'm experimenting with (the Elektor Embedded Linux Made Easy board, based on the GNUBLIN http://en.gnublin.org/index.php/GNUBLIN-Elektor). I'm using the 3.3 ...
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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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84 views

Swap partition in LVM?

I was wondering if putting the swap partition into a logical volume group has any drawbacks (e.g. performance), or would it be "just the same" as having it as a separate primary/logical partition? I ...
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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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1k views

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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Sanity check/cleanup for swap — essentially mkfs.swap

Occasionally I'll have a system crash or be forced to do a cold reboot. Upon rebooting I will get a kernel crash. Get out a rescue disk, rebuild swap, then everything boots fine. The thing is that I ...
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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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KVM and Swap space

suppose the following scenario: a host with 2 GiB runs a few guests using KVM. Each guest does usually not need much memory, they are given 256 MiB each and run services that mostly twiddle their ...
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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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When is swap triggered or how to calculate swap_tendency?

I'm trying to use Redis for production services and trying to avoiding swapping, which is bad for performance. I had learn that swap is triggered by swap_tendency which is depending on ...
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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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Out of Swap - What happens?

On my debian VM machine with 512MB RAM and 348MB Swap, what will happen if i open a 1GB file in an editor and get out of memory? Will it crash the system? Or if not, how will linux handle this? ...
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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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Xeon Phi swap from host's tmpfs

I want to use swap on Xeon Phi (mic0) using RAM from the host On the host: # free -m total used free shared buffers cached Mem: 129022 60312 ...
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Dynamically growing swap file on Debian

I know how to create a swap file and use it as swap. But I have to configure the size of the file beforehand and the space is used on the disk, if the swap is used or not. How do I create a swap that ...
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How to set up properly zram and swap

I'm configuring & compiling new 3.0 kernel. One of the goodies I planned to use for some time (by patching) that was merged into 3.0 is zram. Is it possible to set both hdd swap and zram swap so ...
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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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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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Swap not mounting

I have just installed SolydX (Debian based) onto a laptop with the following specs: -Toshiba Tecra A4 -800MHz Centrino CPU -nVidia 6600 GPU -512MB RAM After installing Conky to monitor my system, I ...
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What does it mean exactly when a processes “Time” has stopped in top?

I'll be looking into why we're getting critical swap alerts, and I'll find something like: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ SWAP COMMAND 14683 user1 30 10 16.0g 772m ...
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Can swap be encrypted per user?

The problem arises for a multiuser computer with encrypted swap, as to how to allow each user to hibernate and resume from hibernation without compromising the security of the other users. I'm ...
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539 views

what does “Read Swap Header failed: Success” mean?

I'm trying to install Arch Linux (from the 2014-04-01 snapshot). I've made a swap file and tried to swapon it, but I got an error(?) message I don't understand. I've executed fallocate -l 512M ...
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Tool to force use FILE instead of RAM

I'm wondering why there is no such tool like ram2swap, similar to cpulimit in parts. E.g. There is program daemon.bin. Let's create temporary swap file ( 1 Gb ): % dd if=/dev/zero of=tmp.swap ...
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170 views

Increasing swap space without reinstallation

I'm running Fedora 20, and I forgot to change my swap size allocation during installation. I have 16G of RAM, so I'd like to allocate 32G of swap space. The install created a swap for me, of only ...
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Can swap be shared safely while hibernating?

Suppose I have two different Linux installations A and B, both using the same swap partition. As I understand, running A or B will cause no problems with swap as only one of them is using it at a ...
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1answer
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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1answer
456 views

Why is swap used when a lot of memory is still free? [duplicate]

In the below 2.6.18 Linux Kernel (Red Hat) server, there is a lot of free memory, but I see some swap is used. I always thought of swap as an overflow when memory has been depleted. Why would it ...
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Does changing of the swappiness need a reboot?

If I configure the swappiness value to another, from ex.: 60 to 0, then I always need to reboot the machine to the changes to take effect? Even when modifying with: sysctl -w vm.swappiness=0
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How to ask for a password to mount crypted swap at boot time on Linux Mint 16 with initramfs-tools? [duplicate]

I use encrypted home folders on my notebook, which prevents use of hibernation on standard setup, because - and for a good reason - besides encrypting the home folder with ecryptfs, it reformats the ...
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Is there a way to prevent SWAP from collecting cached data?

Here is the following info: Do I need more swap? No, disk caching only borrows the ram that applications don't currently want. It will not use swap. If applications want more memory, they ...
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813 views

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 to recover from a boot hang after deleting old swap?

I did a fresh installation of Fedora 20 in the free space of my hard drive after failing to upgrade from the older version. Everything seems to be working fine until I deleted the partition containing ...