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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Is it possible to trigger OOM-killer on forced swapping?

Is it possible to have the system preemptively swap out inactive pages (vm.swappiness), but invoke the oom-killer when the system runs out of RAM (as opposed to running out of memory) and is forced to ...
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Copying large file causes excessive swap

On a mid-class CentOS 6.4/64 server with 32 GB RAM, 3 TB free disk space, operating as KVM hypervisor, I start copying a 200 GB file to a destination in the same local filesystem. In fact, this file ...
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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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Linux running slow with 0 swap left

Our Linux server is responding very slowly. top doesn't show any excessive CPU usage. I noticed that even though there's about 5GB of free memory, the system is using all of swap with no free swap ...
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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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How to stop waking all attached drives on reboot / deactivating swap?

A fresh install of Debian 6.0.6 for a system has 13 SATA drives attached. 12 refurbished WD-10EARS drives are yet unpartitioned. 1 WD1500BLFS drive is configured for OS and swap. Swap partition is ...
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464 views

Spike in swap utilisation without high swap rate

Every Saturday, for reasons unknown to me, one of my servers experiences a spike in swap utilisation. It's not necessarily a problem as there is plenty of free memory available, but I'd still like to ...
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How to reduce size of swap after a system is already installed?

I'm running Debian Squeeze 6.0.5. Does the use of swap memory make my computer run slower? If so, how can I reduce the size of the swap memory after the system is already installed?
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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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Does the order of partitions matter much?

I've just ran a test install of Arch on a separate computer, and now I'm ready to do the real thing on my main one. However, since the guide didn't explicitly recommend it, I did not install with a ...
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2answers
840 views

Where is the virtual memory stored on hard drive?

If a process wants to access a memory address that is not in physical memory, the OS outsources a page frame from physical memory to the hard drive for later use. Where on the hard drive is this data ...
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569 views

Memory management, bias to swapping

I was having 768 MB RAM. In a general day MySQL was using 100-180 mb of RAM and MySQL was swapping 80-120 mb. I was having 50-60 mb free RAM. So I thought I should upgrade. Then I upgraded my RAM ...
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Command for swap info in HPUX itanium and HPUX PARISC?

I need to get commands for swap information in HPUX (both Itanium and PARISC) somebody please help.
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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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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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681 views

tmpfs and vm.swappiness

I have started tuning a bit Linux VM performance on my system (yes. I know that vm.swappiness=0 will kill kittens but I found 30-40 as much better for me as it improved my latency - probably at cost ...
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Solaris swap allocation with mlocked shared memory

I'm having a hard time understanding how Solaris 10 x86 swap allocations work in the presence of mlocked share memory. I wrote a small program that: Gets a 1G SHM segment (shmget) Attaches it to ...
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718 views

What are the advantages of swap on a raid-1 (mirror) device?

What are the advantages of swap on a raid-1 (mirror) device? (in a server environment running linux) I mean, you can just use multiple disk devices in linux for swap. And with swap devices that have ...
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235 views

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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580 views

Java process, swap (/proc Solaris10) memory highly utilized

How can I analyze high swap memory utilization of Solaris 10 for Java processes?
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1answer
373 views

Is there an in-memory compressed swap facility (like Compcache) for FreeBSD?

Is there anything like CompCache for FreeBSD?
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1answer
135 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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How do I configure systemd to activate an encrypted swap file?

My previous question produced the commands to add an encrypted swap file: # One-time setup: fallocate -l 4G /root/swapfile.crypt chmod 600 /root/swapfile.crypt # On every boot: loop=$(losetup -f) ...
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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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zram swap instability

I use Mint 13 Maya with mainline kernel 3.6.3 for Ubuntu Quantal on my Asus P53E Notebook. I use zram swap that comes with the package zram-config. I've noticed that using it the system to hangs at ...
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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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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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1answer
512 views

Can't add swap file on solaris

I'm trying to add a swap file on Solaris 10. I have already created a 2GB file swap.file. Then, I add a swap file with the command: swap -a /swap.file which shows an error: /swap.file: size is ...
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1answer
880 views

KVM and swap problem

So I have a problem, I'm managing a server and the swap partition is way too small at the moment. The machine runs KVM with about 24 VM's on it. The problem is that some of them are rather inactive so ...
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1answer
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Process Monitoring on Solaris

$ prstat -t NPROC USERNAME SWAP RSS MEMORY TIME CPU 164 oracle 5446M 5445M 8.3% 13:47:50 1.6% 52 root 576M 728M 1.1% 42:29:50 1.0% 1 noaccess 300M 273M 0.4% 0:20:54 0.0% ...
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2answers
843 views

Can linux systems on multiple virtual machines share the same swap partition? [duplicate]

I'm trying to save some disk space between multiple systems and re-using the same swap partition (which seems to be fine). I'm now getting into multiple virtual machines and am thinking of a ...
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Is it a bad idea to not have a swap partition on an embedded linux setup?

I have a small embedded linux kernel and file system created via buildroot that is installed onto a compact flash drive running on an x86 board. I am using an initramfs (due to power loss concerns) ...
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Does mkswap check that a partition is a swap partition before formatting it?

I checked the man page for mkswap and was left confused whether mkswap tests whether a partition is of type 82 before formatting it. Background: I am using Ubuntu 11.04, and I had just set up my swap ...
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How is paging managed in the absence of swapping?

How is paging managed in the absence of swapping. If that is the case, how will a page fault be managed? What I meant is, if there is no availability for swapping, then how is Paging managed. I ...
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235 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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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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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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Why my partitions don't show the right capacity on a 4096 byte physical block hard drive?

After reading a lot about why newer 4096 byte physical block hard drives should be partitioned taking care of alignment (Linux on 4KB-sector disks: Practical advice, What is partition alignment and ...
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How to reuse Physical memory in the absence of swapping?

How can I reuse physical memory in the absence of swapping?
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1answer
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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 ...
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1answer
27 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
158 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 ...
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1answer
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Can a VM swap to host main memory.?

While my developer machine has a lot of memory, my vmware VM is 32 bit only and needs some swap space. Can I make it to swap into the host memory? If so, is it possible to use compressed swap space ...
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Swap separation for multiple distributions [duplicate]

I have 3 Linux distributions on my machine (Ubuntu, Arch and Fedora). I allocated half the RAM size (3GB) as swap for each of them. (I have realized that having 3 distributions is not of much use to ...
2
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1answer
191 views

Can I remount as readonly if there's a swap image in use?

When am playing with my Android phone (CyanogenMod 10.1 with kernel 3.0.78), I found this: A script in /etc/init.d/99system.swap.sh It remount /system as rw, and creates an image file in ...
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520 views

Dual-booting Windows 7 and Mint 14 with “something else” option

I would like to do a dual boot of Windows 7 and Mint 14 on my Acer netbook which already has Windows 7 Pro 64-bit installed on an 1 TB hard drive. I have already shrunk the Windows 7 partition to ...
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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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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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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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Linux-swap on reboot

I'm wondering what actually happens to a Linux-swap partition reboot. I've been taking a course in computer organization and while installing/partitioning a new drive I became rather curious about ...