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Questions tagged [swap]

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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Why is my kernel choosing disk swap over 24G of inactive RAM?

Output below is meminfo from a Proxmox hypervisor. I noticed today that swap usage was 90%. I logged into the box and checked and and it seems there is actually 24G of inactive RAM. A couple minutes ...
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How to create randomly keyed swap with Kickstart

I want to create an encrypted swap partition using Kickstart. Instructions on how to create encrypted swap manually are in the related question How to create a randomly keyed, encrypted swap ...
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3answers
61 views

Missing mdam RAID1 array during scan

I have built a new server (Ubuntu 18.04.1) with 4 HDD. My plan is to use RAID1 overall and came up with this layout after investigation: sda, sdb four primary partitions (all as fd) with sda1/sdb1 ...
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Proxmox doesn't recongnize increased swap space

So I tried to increase the swap LV from 8GB to 16GB, but Proxmox web panel doesn't seem to see the change. The LVM increased the space, but Proxmox haven't changed it's panel. Originally lvdisplay ...
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2answers
894 views

Could swap use many inodes?

I have got a graph about high inode use of our server's disk but I haven't got any detailed information (like df -i) so I'd like to guess the reason. Operating System: Red Hat Linux Process: PDF ...
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82 views

rsyslogd uses 435M of swap memory right after restart

I have Centos 7 # cat /etc/centos-release CentOS Linux release 7.3.1611 (Core) fresh rsyslogd # rsyslogd -version rsyslogd 8.36.0, compiled with: enough free memory # free ...
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1answer
27 views

Machine swapping despite there being enough memory

One of our Docker hosts is swapping like hell for no reason - at least, no apparent one (it's a Ubuntu 16.04LTS VM). All Docker containers in summary only use ~4 GB of the 12GB RAM total, but the ...
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136 views

Swap unused, high memory usage and swappiness at 100

I'm running a server with a number of game servers on it. My memory usage is very high, however there is almost no swap usage in comparison. My swappiness is set to 100 total ...
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1answer
71 views

JVM heap is being swapped causing GC go haywire - Tomcat

Info: # of VMs= 4, each with an instance of Tomcat 8.5.* in cluster Apps = 5 war applications- 2 UI applications and 3 Webservices. Java Version = java 1.8.* Configuratin = 2 LTMS and 2 Apache ...
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74 views

Cannot mount swap partition at boot on Amazon Linux 2

I am trying to mount swap partition in etc/fstab on Amazon Linux 2, but it doesn't work on the boot-up process. here the steps I have followed: create swap file: dd if=/dev/zero of=/swapfile bs=1024 ...
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2answers
274 views

High swap usage on CentOS server with plenty of spare RAM

We have a fleet of web hosting servers all running the exact same software & hardware with similar load. One of our server gets very high load that leads to it locking up for brief periods of ...
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111 views

OOM killer kills process though page cache is never evicted

Our servers in production sometimes under load runs into the following issue (Linux 4.10): Application handling the load (webserver) is running at high load. A new job starts (e.g. cron). This ...
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1answer
232 views

How to prevent kernel I/O thrashing in absence of swap memory on Linux?

I had problem with a process spawning very many threads due to a bug, eating up memory, causing heavy swapping to the swap partition. Thus, I switched off swap – which is recommended in server ...
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1answer
249 views

Delete a file that was created with fallocate

I started to create a swapfile. I used this command: sudo fallocate -l 1G /swapfile Then, I decided that I want to make the swapfile in a different path, so I used the command again with the right ...
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291 views

zRam - Increasing Size

I'm running Ubuntu 16.04 (kernel 4.4.0). How to control zram seems to be quite confusing. I'd like to change my zram size from 8G to 10 or 12G (I have a total of 16G). I have gone into /etc/...
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351 views

CentOS 7 swap space used up by qemu-kvm but no si/so operations

I have a DL360 server running CentOS 7 KVM. This server has 256GB of RAM and I have assigned 16GB for swap. My concern is that swap is pretty much used up with only 1GB free. I have 2 other KVM ...
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1answer
91 views

dd using all memory and swap

I have a dedicated Centos 6.9 linux server with a company that crashed due to hardware failure and has been restored with the old HDD's on a usb caddy. I am trying to move lvm partitions over to the ...
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6k views

Why disable swap on kubernetes

Since Kubernetes 1.8, it seems I need to disable swap on my nodes (or set --fail-swap-on to false). I cannot find the technical reason why Kubernetes insists on the swap being disabled. Is this for ...
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563 views

vm.swappiness works differently on CentOS 6 and 7

We have an Hadoop cluster of CentOS 6 (kernel version 2.6.32-504.el6.x86_64) and CentOS 7 (kernel 3.10.0-327.el7.x86_64) servers . All the nodes are configured with a swapinness of 1. All nodes have ...
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AWS ElastiCache Redis - Why has SwapUsage slowly climbed just over 100MB dispite having FreeableMemory available?

Starting around 7/28/2017 the SwapUsage started to climb for reasons I cannot figure out. I have spent many hours Googling and reading AWS documentation. At no point do we run out of FreeableMemory. ...
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1answer
115 views

Volatile Linux with a huge tmpfs and swap partition

I want to deploy Linux on user computers in a way state is never preserved between boots (except state saved explicitly by users on external removable devices). System image will be stored on a read-...
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2answers
108 views

Try to empty buffer and cache

I try to clear the cache and buffer. Because they grow very much and starting use some swap. Will it affect the system? The system running in production. Or is there any other solution? Memory ...
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1answer
218 views

Linux - Use disk as RAM [closed]

I have a VM and in it a process that consumes a lot of memory (~200GB). Some sort of in-memory DB. I need to run it on a standard laptop and I cannot recompile it or see the code. I've added 256GB of ...
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1answer
71 views

I loose the swap every time I restart my Ubuntu server

Here is how I set the swap: sudo /bin/dd if=/dev/zero of=/var/swap.1 bs=1MB count="1000" sudo /sbin/mkswap /var/swap.1 sudo /sbin/swapon /var/swap.1 Every time I reboot/restart the swap is gone. ...
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1answer
64 views

Server responsiveness and swapping

I know how swapping basically works, why it's automatic and why it's generally a good thing. There is, however, a common scenario where I wish I had more control. I write LOB web applications with ...
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198 views

coreos: Why is there no default swap partition?

The standard install of coreos seems to come without a defined swap partition and swap setup. What is the reason for that? Would it be recommended do add swap space in coreos node, which works as ...
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4answers
593 views

How to check the content of swap memory in Linux?

I am trying to find out what exactly uses swap memory in my system. Free reports over 5GB of used swap memory, but all processes use only 24MB of swap. I suspect that swap might be used by a tmpfs ...
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1answer
205 views

My server virtual memory full

occasionally my server hits 100% usage on virtual memory and I don't know if that is something alarming or not? ( this happends gradualy to fill to that percent over 1-2 weeks from clean swap) I ...
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1answer
265 views

RAID-10 for swap: Optimal chunk size

I would claim that if I had a RAID-10 array which is used as swap device only, a chunk size of 4K would be perfect as it matches the page size. Am I right?
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1answer
165 views

swapon & hibernate on power key

I have a laptop & I run Arch Linux. My laptop has a spinning hard drive rather than an SSD, so I hate swap. However, I need one to hibernate, and I want my laptop to hibernate every time power key ...
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2answers
971 views

docker container + java application -> swap used -> why?

There is docker container with java application inside. docker inspect dbc237493367 | grep -P '((Memory)|(Pid))' "Pid": 16283, "PidMode": "", "Memory": 10737418240, "KernelMemory": 0, "...
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2k views

ESXi - distinction between Host Cache, VM Swap File, System Swap, vFlash?

In ESXi 5.5, the host config has a number of similar sounding settings related to swapfiles and caches of various types. I understand the principles of write-back/write-through disk cache and ...
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56 views

Red Hat Enterprise Linux 6 lvremove succeeds but causes system to not boot

I started with a fresh install of RHEL 6, and it created a default swap as a logical volume (/dev/vg_hostname/lv_swap), along with the root (/dev/vg_hostname/lv_root) mounted as / I then created a ...
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1answer
3k views

Ansible throws an “ ERROR! A worker was found in a dead state ” error

When I run a playbook that simply copies a directory from one place to another, ansible throws ERROR! A worker was found in a dead state Error. After some googling, it looks like this is caused by ...
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2answers
317 views

Is adding Swap on a server with an SSD discouraged?

In this tutorial Digital Ocean explain how to enable swap on Ubuntu 14.04. I arrived at this article after experiencing some issues with my server and this looked like it could help. However, they ...
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1answer
408 views

adding new partitions to a device the containing root partition [closed]

On virtual box, I have my root file system mounted on the LVM: # df -h | head -n 2 | tail -n 1 /dev/mapper/cl-root 1.5G 951M 404M 71% / The LVM is mounted on /dev/sda2, and /dev/sda has the ...
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1answer
172 views

Linux swap file not being used [duplicate]

One of my database server running mysql/debian is out of memory. I added a swap file but as far as I know it's not used by the system. I can confirm that the swap is enabled when I execute the free -...
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1answer
110 views

Database files and the system swap space on the same disk?

Why is it problematic to configure the database files and the system swap space on the same disk? What can happen?
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1answer
77 views

Can swapped memory be read directly by java?

When the kernel swaps stuff to disk, can this data be subsequently read by the process directly from swap? or it must absolutely be put back into physical ram (thus generating si so activity in vmstat)...
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1answer
359 views

LVM logical volume for /home partition corrupted after lvresize to increase swap space Fedora 25

I added 6GB of memory on an older Dell PowerEdge 1850 that we use just for backups to an attached hardware RAID from Promise Technology called a VessRAID connected by iSCSI. After a few weeks I ...
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5answers
7k views

Should I be concerned that swap is being used on a host with nearly 40GB of free memory?

I have a production host, below: The system is using 1GB of swap, while maintaining nearly 40GB of free, unused memory space. Should I be concerned about this, or is it mostly normal?
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2answers
85 views

Increase Swapfile on operational system

new to this and I am trying to figure what will be the best way to go on about this. I have a system that I need to increase its swap file, I realized that the swap partition is not lvm so that is ...
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1answer
75 views

Swap partitions between /home and /var

I have a server with 2TB (Raid, 2x2TB), and this partition schema / => /dev/md2 - 20GB /home => /dev/md3 - 1.8TB This is a ISPConfig server, so we need many space in /var and almost nothing ...
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2answers
243 views

why after swap increasing and swapoff and swapon , swap total return to the previous value

in my Linux redhat machine ( version 5.x ) I perform the following steps in order to increase the swap from 6G to 8G lvcreate -n swap -L 2g /dev/rootvg mkswap /dev/mapper/rootvg-swap1 swapon /dev/...
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1answer
301 views

linux + how to know when swapoff -a should be ended

on my linux redhat machine I perform swapoff in order to drop swap pages that stays in cached swap! swapoff -a I waiting until now one hour and swapoff still work can we see some process or ...
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1answer
2k views

Lack of free swap space on linux Zabbix server

I have been getting this Lack of free swap space on Zabbix server on my aws instance via zabbix monitoring. I am thinking of creating say 2 Gb of swap space. Do I risk loosing or interfering with ...
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4answers
2k views

Can I run an Oracle server without swap?

Official Oracle docs say that for a machine with more than 16GiB of RAM we need to allocate 16GiB of swap. Our servers are RHEL 7 and have 256GiB of RAM. DBAs do not want to see the system swap, so ...
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1answer
882 views

linux redhat + swapoff is stuck not return prompt

I do the following steps in order to increase the swap size but when I start with swapoff /dev/mapper/rootvg-swap , then its stuck for along time and not return the prompt why we can do to solve ...
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2answers
923 views

Using swap even though 20GB free memory, swappiness=0

We have a CentOS 7 server that goes into swap a little bit about once a week, despite having > 20GB of available memory, and swappiness is set to 0. We want to be able to use swap as a sort of ...
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2answers
264 views

Active process swapping despite free memory

For some reason our system starts swapping (actively used memory) at around 60GB used memory. (see edit below, it seems I/O and disk cache usage, even of previously run processes has an effect) ...