Linux divides its physical RAM (random access memory) into chucks of memory called pages. Swapping is the process whereby a page of memory is copied to the preconfigured space on the hard disk, called swap space, to free up that page of memory. The combined sizes of the physical memory(RAM) and the ...

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2answers
60 views

Why is my server swapping at all?

Munin shows ram that is doing nothing most of the time. But swapping still happens. Quite regularly actually, bogging down the hdd. Or am I seeing the ram graph in the wrong way? How would I go ...
-1
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3answers
29 views

Linux makes cache for swap. what for?

It looks like joke: swapfile on "ramdysk" in 64bits system? I look into file: /proc/meminfo and made some investigation. Look for line: SwapCached: nnnnn kB . One is what I don't understand. ...
0
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3answers
94 views

Is there any reason to NOT have a swap file on CentOS (DigitalOcean)

I'm running a site on DigitalOcean with CentOS 6.5. As has been noted elsewhere, DigitalOcean servers are by default configured without any sort of swap, and I'm wondering if I should add one. I ...
0
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1answer
26 views

Debian 6 - Linux 2.6.32-5-amd64 - Samba server with 32GB swap - how should i reuse it?

today i have the mission to tuning a Debian samba file server, previously i never ever touched it. RAM = 16GB SWAP = 32GB first of i ran a parted -l and a free -h and i saw one 3TB hdd: /dev/sda ...
2
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1answer
93 views

My Ubuntu VPS is not using available swap, even if OOM. What to do?

I recently added 1 GB of swap to my Ubuntu virtual private server to prevent MySQL crashes on RAM overloading. I followed this tutorial. I use htop to monitor resources. When I use loadimpact to test ...
1
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1answer
63 views

Server failure in minutes due to high httpd-apache use (attack or bug)

In the last week suddenly I get errors for my server. I try to access my website I get 503 errors. When I check top and other things I see these: 60-65 httpd (apache) processes. (Normally I have ...
3
votes
2answers
91 views

How can I keep important VMs in memory without disabling swap?

VM Host -> Xenon E5-2440 w/ 48G mem... Everything runs CentOS6.5 (2.6.32-431) I have 4 guest VMs running each w/ 2G of memory. Their disk images are local files. The host machine is also running a ...
0
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1answer
45 views

OpenVZ vSwap Host Configuration

I wish to allocate vSwap memory to my OpenVZ containers. Where does OpenVz get the vSwap memory from? If the host were to run out of physical RAM, would the host start to use its own normal swap ...
0
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2answers
131 views

KVM under CentOS, swap exhausted, physical memory available

I've had a test CentOS KVM host running for about a week now with 3 CentOS guests. There's 12GB physical RAM with about 7.5GB actually allocated to VMs. These VMs aren't even being used yet as the ...
0
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2answers
41 views

Linux swap, linear write/read

i'm puzzled if linux writes and reads on swap sequentially . Now i'm analizyng pressure on swap partition and it's strange that utilisation is near 90% (util column in iostat ) but throughput is ...
0
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1answer
71 views

Why the system information message when accessing an Ubuntu server doesn't match free -m?

Each time I SSH into my AWS Ubuntu servers I see a system information message, showing load, memory usage and packages available to install, like this: Welcome to Ubuntu 12.04.3 LTS (GNU/Linux ...
0
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1answer
74 views

Transfer used ram to swap and free more physical ram

I have a vps with 256m physical ram and 512m swap space, I am trying to use a software that need more than 256m and less than 512m ram, so it uses swap. The problem is at some moment of the ...
5
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2answers
2k views

How to find what is using linux swap or what is in the swap?

I have virtual linux (Fedora 17) server with 28GB RAM and 2GB swap. The server is running mysql db that is set up to use most of the RAM. After some time running the server starts to use swap to swap ...
1
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1answer
163 views

Ubuntu Server hanging on adding swap

A fresh install of Ubuntu Server is refusing to boot and hanging on "Adding 524284k swap on /dev/mapper/test--vg-swap_1. Priority:-1 extents:1 across:524284k I can get around this by dropping onto ...
0
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1answer
73 views

SWAP reducing SSD write speed?

My SolusVM graphs have been showing 8Gb Swap usage even though the RAM is never over 50% used. Is it possible that virtual machines going into swap will reduce the IO of the SSD?
4
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1answer
248 views

Background discard on swap partitions on Linux + SSD

Problem I want to enable background TRIM operations on a swap partition within a SSD disk on Linux. According to several articles, e.g. this one, the kernel detects this configuration and ...
0
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2answers
135 views

Moving a process to and from swap [closed]

I've got serveral processes (game servers) on my linux server that use up 50MB of RAM. They are not constantly being used, and I'd like to be able to run more instances than my RAM capacity allows. I ...
2
votes
2answers
984 views

How can I create a swap partion on Amazon EC2 with ephemeral storage?

This is the output of df -k: Filesystem 1K-blocks Used Available Use% Mounted on /dev/xvda1 10317860 7059008 2734732 73% / none 847584 0 ...
1
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0answers
130 views

Is there ever a reason to use tmpfs instead of or in addition to zRAM?

I'm thinking about using zRam on my server. From what I've read about zRam, it apparently does everything tmpfs does and more. Once zRAM is working, is there any reason to keep tmpfs around? Is there ...
0
votes
0answers
34 views

apache server has weird behavior

Okay, this one's weird for me. I have a wordpress mu site under a dedicated server. It runs Apache 2.2.21 and php 5.3.10. When msn and google bots crawls my site the system crashes. The system crashes ...
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votes
1answer
64 views

Am I having too much swap? [closed]

Am I having too much swap space if my server is a 8GB physical ram and I would like to set my swap to 16GB. I am planning to use this server for shared hosting would like know.
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0answers
96 views

Why is /proc/meminfo reporting misleading SwapTotal

Consider this: [skrat@apex geri]$ cat /proc/meminfo | grep SwapTotal SwapTotal: 18438120 kB [skrat@apex geri]$ swapon -s Filename Type Size Used ...
0
votes
2answers
133 views

How do I resize full root or swap partitions in RAID?

It all began a couple weeks ago: When I try to use vi I get "E297: Write error in swap file $ echo "test" > test produces -bash: echo: write error: No space left on device My bash history is ...
0
votes
1answer
108 views

Should I create a 8 GB swap file on my amazon image?

I have an Amazon image with 1 root image, 1 image that I uses for websites and is only using 25%, and 1 image "unused" So I thought... maybe I can use that unused image for a linux swap file. Since ...
1
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3answers
281 views

What is the danger in having a fully used SWAP in an Ubuntu server?

One of my Ubuntu servers' swap partition is full. What are the dangers and/or performance ramifications of this situation?
1
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1answer
155 views

Server crash when creating a swapfile on a running machine (CentOS Linux)

I created a swap file with root on a running server, using swapfile creation guides which I found on the net (http://blog.serverbuddies.com/adding-additional-swap-space-to-your-linux-server/m Create ...
1
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1answer
263 views

e2fsck on a low-memory machine: can I get more out of scratch_files or swap?

I am running CentOS 6 on a 32-bit machine with 1 GB of RAM. I have a 1TB external HDD that I am trying to run e2fsck on. It runs for about an hour and a half and then fails with Error storing ...
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votes
2answers
110 views

Server with high consumption of physical memory; swap is not being used [duplicate]

Please, I need a help. I have a Linux that has the following scenario of RAM memory consumption: root@cpro15623 [~]# free -m total used free shared buffers cached ...
1
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1answer
1k views

How much space is in a Solaris /tmp filesystem?

On Solaris, the /tmp filesystem is a filesystem of type "tmpfs". It's implemented in the kernel by allocated space from the virtual memory pool. That means allocation interacts with the available RAM ...
1
vote
1answer
224 views

CentOS webserver memory overflow - cannot log in

Few days ago, my CentOS 6.2 webserver with ISPconfig 3 went down to the extent I wan't able to log in via SSH nor using a console. The console was full of messages "out of memory, killing process, ...
3
votes
1answer
915 views

Why does host swap out VMs when there are 16GB of buffer cache and swappiness = 0? [duplicate]

I have a desktop running Ubuntu Quantal using OpenStack Folsom on an Intel i5 with 32 GB RAM and 2 GB swap. I'm running 7 VMs each sized like a EC2 m1.small, so 1.7 GB RAM each. I'm using KVM. As I ...
2
votes
2answers
238 views

Linux process swap usage is greater than the overall system swap usage

I have a strange problem that when I run top command it shows that some processes are using around 1.5GB of swap space but then the overall usage of the system swap is way to less to something around ...
1
vote
0answers
172 views

Couchbase RAM Usage & Clear cache

I am in a company that is a fan of Couchbase ( Version 1.8.x). Our Couchbase servers always has RAM around 48 GB. Couchbase Total Allocated is 39 GB. Couchbase In Use around ~ 15-29GB . Note ...
2
votes
1answer
69 views

Is there a way to free swap?

After using vmware player with some virtual machine, it seems like my swap stays quite occupied and it doesn't changes unless i reboot it. However, regularly swap is not used much by other ...
1
vote
2answers
188 views

Ubuntu: forcing processes into swap, or into RAM

I am now solving the following problem on Ubuntu: Is it possible to specify if one process should run only in the RAM (i.e. is not allowed to swap) or reversely only in the swap part? I mean that the ...
12
votes
3answers
3k views

How to disable swap files in ESXi?

We are running a few Solaris / Linux VMs on ESXi that contain very sensitive encrypted data that eventually get decrypted as required in memory. Everything is fine, except for the ESXi swap files ...
1
vote
1answer
179 views

How to instruct linux not to swap out hot pages of mmaped files?

I have a server where I run worker processes that mmap serveral rather big read-only "dictionary" files (~8GB total). Tests showed that they actively access only around ~1GB worth of the pages in ...
0
votes
1answer
67 views

Swap files in Cloud Infrastructures

At our company we set up an OpenStack Cloud and are currently creating internal guidelines for creation of OS templates / images. One controversial topic was if we should provide swap inside the VM ...
1
vote
0answers
104 views

Limiting memory usage and mimimizing swap thrashing on Unix / Linux

I have a few machines that I machine that I use for running large numbers of jobs where I try to limit the number of jobs so as not to exceed the available RAM of the machine. Occasionally I ...
0
votes
1answer
709 views

How much RAM do I need to run a forum using Nginx, Gunicorn, Django?

I started an ec2 instance (micro) to test the amount of memory I have available to run a website but I was expecting having a bit more. So my question would be: How much RAM do I need to run a site ...
1
vote
2answers
111 views

How can I determine the method of this DDoS attack? [duplicate]

My server went down earlier - looks like a DDoS. A spike in traffic to around 13mbit, the swap goes from idle to maxed in about 5 minutes, and server stops responding. I would like to protect ...
0
votes
1answer
92 views

how do OS deal with dirty page if there is no swap space [closed]

As in text books OS will move dirty pages to swap space based on LRU algorithm and make space for new process in RAM. But how do OS do this if there is no swap.
4
votes
1answer
85 views

Is it sensible to use SLC swap as a RAM substitute on a VM host?

I have a few oldish servers running virtual machines but they are limited to 16GB RAM and that limits the number of VMs I can run and the options for RDS. I've added a RAID1 array of two Intel 311s: ...
0
votes
1answer
599 views

Very high Magento/Apache memory usage even without visitors (are we fooled by our hosting company?)

I am no server guy and we have issues with our speed so I come here asking for advise. We have a VPS with 2 cores and 2gb of RAM at a Magento specialized hosting company. Over the course of the last ...
1
vote
1answer
115 views

Swap space maxing out - JVM dying

I have a server running 3 WordPress instances, MySql, Apache and the play framework 2.0 on 64m initial & max heap. If I increase the max heap of the JVM that play is running in even by 16m I see ...
0
votes
1answer
71 views

how can I tell if there is a cpu trashing on my linux machine

I want to write a script that will kill my processes when my machine is doing "too much" swapping of process memory from disk to memory. What is the best way to determine that? I saw top has %wa and ...
3
votes
2answers
628 views

How is htop “Swp” calculated?

When I run htop (on OS X 10.6.8), I see something like this : 1 [||||||| 20.0%] Tasks: 70 total, 0 running 2 [||| 7.2%] Load average: 1.11 ...
1
vote
1answer
1k views

Using tmpfs + a very large swap partition for /tmp instead of a regular filesystem?

I have Linux server and I have a spare 500GB disk partition. I wanted to format it and use it for /tmp. The server occasionally runs some large data processing tasks so it can happen that /tmp will ...
1
vote
2answers
1k views

Should I use swap in KVM guest?

Now I'm trying to create KVM templates with CentOS and I'm not sure should I create swap partition on guest OS or not. In future it will be lot's of small VPS with 256-1024Mb RAM and if swap partition ...
4
votes
2answers
211 views

How to read `top`. Process list says processes have swap but overview says no swap is being used

I am using top to monitor my server. The swap row reads Swap: 1044220k total, 0k used, 1044220k free, 148544k cached I have hit O p to sort by swap. PID USER PR NI VIRT RES ...