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 does mkswap work? What is in the swap header it creates?

I am looking at mkswap and trying to understand how exactly it works. From what I understand, it sets up Swap space on a partition by creating a swap header. How large is this swap header? Is it one ...
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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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1answer
100 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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1answer
63 views

Permanent swapping with lots of free memory

We have a Linux server running Debian 4.0.5 (Kernel 4.0.0-2) with 32G RAM installed and 16G Swap configured. The system uses lxc containers for compartmentalisation, but that shouldn't matter here. ...
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How to safely turn off swap permanently? (on Debian Jessie)

I fresh installed Debian Jessie with default partitioning on an SSD drive. My current disk partitions look like this: As I have 16GB RAM, I think I don't need swap. On Windows, I had it turned off ...
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2answers
385 views

Is clearing a full swap necessary / wise?

We have a linux machine, in which the swap partition gets filled to the limit from time to time. There's still enough of RAM free, so there should be no risk of running out of memory. The usual course ...
3
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1answer
34 views

How to prevent swapping on Mac OS X?

I am inclined to run Tails through a virtual machine so that I could chain two VPNs. One running through the host Mac osx and one more running from inside the virtual machine that's running Tails. ...
2
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1answer
26 views

Zeroing out FreeBSD swap space?

I'd like to zero-fill the partitions/slices in my FreeBSD VMs in order to provide for better compression for archival. For those partitions/slices with file systems the process is no problem for me to ...
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3answers
97 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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1answer
19 views

Old Xen Installation Unable to be Formatted

I recently tried to format a disk that had an old Ubuntu 14.04 partition and a Xen Swap Disk partition. I am currently running the Ubuntu Live CD and trying to access my partitions on the drive for ...
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3answers
97 views

Linux, SSD and swap

This article suggests not to create a swap space on an SSD drive in order to reduce its wear. On the other hand, it suggested here that swap space positively affects performance. Would it be a better ...
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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 ...
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44 views

How to create Swap from already created mount points

I have prepared a CentOS 6.5 with all mount points at formatting time, including swap. Now, when I am trying to run command swapon, it shows 0 0 0. And when I am trying to create it again using ...
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FreeBSD shared swap partition with linux

What to do, to run this commands before Archlinux calls swapon -a ? mkswap /dev/sdaX swapon /dev/sdaX Just in case, /dev/sdaX was created in FreeBSD 10.1 enviroment, as soon as FreeBSD doesn't ...
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1answer
45 views

Linux Swap Space

I have got 32GB memory. SSD and NonSSD drives. I installed linux to NonSSD drive but i prefer SSD for /var directory and i didn't create swap space because there is high memory. I know physical ...
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Swap on tmpfs (Obviously a bad idea, but is it possible?)

This question originated with a joke between co-workers about increasing performance by moving swap partitions to a tmpfs. Clearly even if this is possible, it's not a good idea. All I want to know ...
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1answer
54 views

How to calculate Swap warning/critical dynamically through script?

I have used SAR in my below script and is trying to run on individual servers for my nagios monitoring. Can someone please suggest how i can get the swap warning and swap critical values in my check ...
3
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1answer
28 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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1answer
57 views

Swap suddently vanished from Debian?

Everything has been going fine for 6 months now until my swap suddently vanished today. Now that I look into it, I find that my disk partitionning is a bit weird. What happened to it and what should I ...
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What is kswapd_low_wmark_hit_quickly from /proc/vmstat

What does this parameter mean? # cat /proc/vmstat | grep low kswapd_low_wmark_hit_quickly 2
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1answer
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swapon command is not listing the lvm name

I am facing issues with swapon -s command. It is displaying some other filename instead of my lvm name which i have given ( swap is LVM partition ) swapon -s command is not listing my LVM Name for my ...
0
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1answer
147 views

Why and how is swap improving performance, and can I disable it? [closed]

I have a laptop with 8GB of RAM running 4.0.4-2-ARCH. Recently, I installed Android Studio, and bam, my normally pristine system was suddenly stuttering and all out freezing (more than once). Before ...
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1answer
47 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 ...
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1answer
59 views

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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1answer
61 views

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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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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41 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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26 views

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
37 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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3answers
42 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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0answers
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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 ...
0
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1answer
102 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
45 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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63 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 ...
0
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1answer
123 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 ...
2
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1answer
65 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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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 ...
0
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0answers
68 views

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
112 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
109 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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1answer
43 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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233 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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2answers
29 views

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 ...