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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Linux doesn't drop FS Caches. Instead Memory starts Swapping

I'm quite confused about this behaviour of linux memory caching. total used free shared buffers cached Mem: 15953 14188 1765 64 ...
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What happens when a tmpfs volume is full and swap is full? Is Linux's OOM-killer involved? [duplicate]

I understand that if a persistent / disk-based volume is full, files need to be explicitly deleted to free up space before more can be added. Further, I understand that if memory is exhausted, the ...
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65 views

What sets the size of tmpfs? What happens when its full?

What sets the size of the tmpfs? (On my machine it resides in /dev/shm) I can see its entry in /etc/fstab, but no notation of its size. When checking with df -h, it seems to be half the size of the ...
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how to check what is in swap?

On my system i have some amount of swap used: undefine@uml:~$ free total used free shared buffers cached Mem: 16109684 15848264 261420 633496 ...
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1answer
21 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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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 ...
3
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1answer
29 views

Can swap space accomodate single process?

From what I understand, the swap space can be used to swap out inactive processes to free up memory. But can a single process take advantage of swap space? For example, if my system has little memory, ...
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2answers
24 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.. please advice..
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Ubuntu 14.04 using 100% swap space, with more than 40GB free memory, why?

I'm a bit at a loss trying to figure out why this would be the case. Can anyone provide some helpful ideas on troubleshooting this? $ free -m total used free shared ...
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58 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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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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1answer
41 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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Making Linux read swap back into memory

The Linux kernel swaps out most pages from memory when I run an application that uses most of the 16GB of physical memory. After the application finishes every action (typing commands, switching ...
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32 views

Out of Memory with unused memory and swap

I have a strange error on my Raspberry Pi2. System is archlinuxarm. Short after boot (about 30 secs), the system states that it is out of memory, resulting in closing many applications, most time ...
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66 views

Process Being Killed due to low swap

I'm running a python (2.7) script on mac osx yosemite. The script is fairly computationally intensive, certainly bumping up against my machine's RAM limitations. The computer crashes and restarts ...
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1answer
50 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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130 views

Is there any relationship between memory fragmentation and whether or not swap is enabled on a system?

One of the answers to Do I need swap space if I have more than enough amount of RAM? got me wondering if there is any relationship between memory fragmentation as measured by cat /proc/buddyinfo and ...
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3answers
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Is swapping enabled by default on common operating systems?

As a result of this question, I was a bit confused. After some research I found that swapping is enabled by default on Mac OS X. Swapping was furthermore introduced in Windows 3.0, so I believe it is ...
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Installing Mint 17.1 with swap on different drive?

Installing Mint 17.1 Cinnamon, I used the "something else" mode to set the partitions for root and home. But, it only showed sda and I could not find any way to select a different disk! I installed ...
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Do I need swap space if I have more than enough amount of RAM?

From what I understand, the purpose of a swap partition in Linux is to free up some "not as frequently accessed" information from RAM and move it to a specific partition on your harddrive (at the cost ...
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1answer
49 views

How to find the swap uuid

I am in the process of setting up a raid. sda was used during the installation and I just copied the partition table of sda to sdb like so: $ sudo sfdisk -dL /dev/sda > partition_table_sda $ sudo ...
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1answer
60 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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30 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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Can swapping be disabled on the application level?

I'm currently using thunderbird with gnupg to read encrypted emails. If I understand the swapping behavior correctly, the memory pages containing the decrypted emails might be swapped out and leave ...
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Java process gets killed frequently by OOM - Killer on upgraded hardware

I am running solr on an Ubuntu server along with 4 other java processes. Current index size is 30 GB. My solr process gets killed frequently in few hours. It clearly mentions that its an OOM killer. I ...
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126 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 ...
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Delete a swap partition without user interaction

I have a VM with a swap partition on /dev/sda5. The problem is fdisk is interactive so I cannot use it to delete a partition without user interaction. How do I delete the partition in my ...
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44 views

ZFS swap vdev space accounting

I am on an OpenSolaris system with ZFS on it. I am trying to determine the exact space usage and/or reserved space for the swap vdev. root@storage:~# zfs list NAME USED AVAIL ...
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190 views

When does swap start to be used? When does a process get an out of memory error and be killed?

When does swap start to be used? Is it when the memory is fully used? Or when the memory hasn't been fully used? When does a process get an "Out of memory" error and be killed by the kernel? is it ...
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1answer
61 views

Does a Linux server use swap space of an SSH client? [closed]

I currently am SSHing into a Linux server via my mac's terminal program. Afterwards, I run whatever simulations and calculations I need to do. However, I noticed that after I log in, it says on the ...
2
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1answer
69 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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0answers
46 views

Detect whether a swap partition is in use by a hibernated system

Is there a way to detect whether a swap partition contains the memory of a hibernated system? More specifically: suppose I have a Linux installation and that I hibernate it. This means that all the ...
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43 views

Why is my computer sluggish after downloading a lot?

When I download a lot of data (e.g. 3GB) in one go, using a program such as Transmission or Wget, progressively during the downloading, and after it has has finished, the computer always seems ...
0
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1answer
109 views

What is the difference between MAC OS X “Virtual Memory” and Linux/Unix Swap? [duplicate]

I would like to understand the difference of MAC OS X "Virtual Memory" and Linux/Unix Swap. I ask this because I observed that MAC OS X "Virtual Memory" seems to work way more efficient (in desktop ...
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unlimited tmpfs

How to have the advantages of tmpfs and not be limited to its small size? I'm thinking of a shell script that runs as a daemon, monitors RAM and adds more swap files in specified folder, when memory ...
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172 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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1answer
88 views

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 ...
2
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1answer
33 views

Effects of SWAP failure

A team member has created a swapfile on one of our machines which needed more swap. And he created it on a filesystem on SSD. While our servers are not swapping a lot and probably safe to keep the ...
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1answer
232 views

Opening files of size larger than RAM, no swap used.

I found myself asking this question while doing small experiments and reading upon how memory is managed in Linux. I have a 64-bit Centos 6.5 machine with 512M RAM and 1G SWAP. I created a 1GB file ...
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2answers
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Does the debian setup with lvm also encrypt the swap partition?

I'm planning a fresh debian install on my notebook and want to have full disk encryption. But I mainly hibernate, which is why I want my swap to be encrypted as well. During the graphical expert ...
2
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1answer
195 views

Why does mouse and keyboard freeze when Linux swaps

I have noticed that under Linux, when there is heavy swapping, the mouse cursor freezes, and even CapsLock or Ctrl+Alt+F1 don't work. The system uses the deadline I/O scheduler but this should not ...
2
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2answers
2k views

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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0answers
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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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1answer
63 views

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 ...
0
votes
1answer
149 views

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 ...
3
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1answer
156 views

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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365 views

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 ...
2
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1answer
275 views

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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143 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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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 ...