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 ...

learn more… | top users | synonyms

1
vote
2answers
1k views

How to make Swap work? CENTOS 5.7

I've got a Centos 5.7 running Magento with nginx. I also got there 10GB of Swap. But the os never use it. How can i make it work?
1
vote
2answers
129 views

Swap on Ubuntu and CentOS

I have two questions, which is both related to a swap partition or file. Is it possible to install either Ubuntu or CentOS without a swap configured, without tinkering? Live CDs like Ubuntu, is ...
2
votes
1answer
756 views

Server refuses to use swap partition

We are running a server with 23 cores (cpuinfo shows 22 as the highest process number) and 66 Gig RAM. The development team here is running some apps, which hogs memory. I have observered that: 1. ...
0
votes
1answer
128 views

Kill or revive a process based on system memory usage

Consider a system with limited memory, like a smallish VPS. Suppose there are a handful of processes that need to stay alive, and one process "P" that would be nice to have around, but is not ...
6
votes
1answer
6k views

How to free swap without rebooting (to avoid hourly alert emails)?

I get alert emails whenever swap usage is at 100%. In my case, swap usage doesn't reduce later on (even though memory is free) so I get an alert email every hour. How can I reduce swap usage without ...
12
votes
8answers
10k views

Should I completely turn off swap for linux webserver?

Recently my friend told me that it is a good idea to turn off swap on linux webservers with enough memory. My server has 12 GB and currently uses 4GB (not counting cache and buffers) under peak load. ...
8
votes
3answers
16k views

How to increase swap size?

Recently, I put more ram into my server and now I have got a total of 24GB of RAM. Originally, I setup the OS to have a 2GB swap size. /dev/sdc1 1 281 2257101 82 Linux ...
2
votes
3answers
967 views

top reports swap at 100%, free memory available

On RedHat 5 servers, we see top reporting swap has 0k free. vmstat shows the same amount of swap used, but no paging. We kill our only app, and top still reports 100% of swap used. If we reboot, ...
0
votes
3answers
266 views

Socket and Swap Space

I have a system that is running out of memory and has a lot of open connections. but my swap space is not being used up that much. Can socket/socket file descriptors use swap space? This is for a ...
2
votes
1answer
322 views

Windows Server: Prevent process swapping/paging

Is there a possibility to prevent swapping for a single process? This process is an in-memory-database and should not be moved to virtual ram. all other processes should still be swap-able. I ...
2
votes
2answers
325 views

Should swap space be in a logical volume, or directly on disk?

What are the benefits of putting swap into a logical volume over using direct disk access? For example, with a fresh, default install of RHEL5 or 6, a volume group is created on the default disk ...
2
votes
1answer
270 views

Ubuntu Swap on EC2 with an EBS root

Running Ubuntu 11.04(natty) on an EC2 micro instance. Setup 1gb swap file at /mnt/swap. Works fine until I reboot and then the swap is not active. I can activate it manually using swapon -a, but my ...
4
votes
1answer
9k views

why is kswapd using high CPU on an idle system?

I have an idle Linux centOS system and yet kswapd is using 100% cpu. All I have running is a single bash session with top running.... I have 32G RAM and yet kswapd is constantly using 100% cpu for ...
6
votes
3answers
24k views

How do I tell what process is causing kswapd to be in use?

I see kswapd using 100% CPU... how can I tell on which process's behalf kswapd is being used so much?
8
votes
1answer
628 views

Create swap file on a running Linux machine

Our company web sites have just been moved from a shared host to a VDS, as the hosting company plans on retiring the less than completely reliable shared hosting server(s). The VDS only has 256MB of ...
8
votes
4answers
4k views

How to create a randomly keyed, encrypted swap partition, referring to it “by-uuid”, on Debian?

It is sensible that if you have any sort of block device encryption implemented on your GNU/Linux system, to encrypt your swap partition too, as any decrypted data may be written in cleartext at any ...
2
votes
2answers
117 views

Tuning windows virtual memory/paging for a specific workload

I have a specific ram-intensive program I run which slows down my entire system for hours after each run - does the Windows NT 6.0/6.1 kernel have any tunables to encourage processes' working sets to ...
1
vote
1answer
185 views

Reasonable memory limit alarm for 2GB machine running RHEL5 OS

We have a bunch of servers with the below configuration: Dual Core single processor 2GHz with 1 MB Cache. Swap is enabled with 1GB limit Memory - 2GB OS - RHEL5.3 64bit One of our alarms is ...
9
votes
2answers
5k views

Why does Windows 2008 use swap before the memory is full?

I administer a Windows 2008 server (well, on Amazon EC2) running IIS and a .NET4 Web app. I got a memory alert the other day and went and looked, and sure enough the process memory had grown over ...
3
votes
1answer
400 views

How does the Windows /3gb switch relate to physical RAM?

I have a 32-bit Windows server with 4 GB of RAM. From reading various articles on the web, I reached the understanding that enabling the /3GB switch in boot.ini would mean that of my 4 GB of RAM, 3 ...
3
votes
6answers
5k views

What and why is my swap space used under linux

on my linux system I get these stats from top: Tasks: 155 total, 1 running, 153 sleeping, 0 stopped, 1 zombie Cpu(s): 1.5%us, 0.3%sy, 0.0%ni, 97.4%id, 0.7%wa, 0.0%hi, 0.0%si, 0.0%st Mem: ...
1
vote
2answers
1k views

memory leak? RHEL 5.5. RSS show ok, almost no free memory left, swap used heavily

i encounter a very instresting problem, and it seems that some physical may disapper quietly. i am very puzzled, so if anyone could give some help, I would be very appreciated. here is my top show: ...
0
votes
1answer
901 views

SWAP CRITICAL - 100% free (0 MB out of 0 MB)?

ANy ideas how to address this issue ....I am on ubuntu 10.04 on amazon ec2 here is the image
3
votes
5answers
1k views

How to prevent going to SWAP?

We have a critical application which uses pretty much of our RAM memory. At most time the application stays in RAM, however there are some situation (e.g. when some other applications and deamons ...
0
votes
2answers
352 views

swap on dev + but get mount dev + how to swap dev anyway?

when I do the: mkswap /dev/sda3 mkswap: error: /dev/sda3 is mounted; will not make swapspace. how to perfrom mkswap anyway , David
0
votes
1answer
334 views

swap never used, system freezes with high HD action when RAM is short

My system freezes quite often when run out of memory, I have 2GB and using netbeans, chrome, firefox and a few other apps this is consumed completely. Seems to me since I upgraded to ubuntu natty. ...
0
votes
4answers
4k views

linux redhat 5.4 - swap while memory is still available

This server is swapping using 100% (15G swap disk) while it still has 30G free, I've been looking arround but can't figure why this is happening, my understanding was not to use swap if memory is ...
0
votes
3answers
116 views

Paritition an LVM LV

I have an LVM logical volume (LV) and would like to create partitions within this LV to provide an ext3 partition and a swap partition. This LV would then get mounted as a disk to a virtual machine ...
4
votes
2answers
840 views

Linux: Where to put the swap file

Are there any conventions on where to put swap files on Linux? I usually just create them in /var/swapfile, but that seems a bit too high up in the hierarchy.
2
votes
2answers
824 views

Resizing swap partition (RHEL 5.x)

Following is how parted print looks like: (parted) print Model: VMware Virtual disk (scsi) Disk /dev/sda: 26.8GB Sector size ...
0
votes
2answers
433 views

Linux swap partition not recognized on reboot

When I reboot my Linux server the swap space reads 0 in top. I am running a vanilla install of CentOS 5.2 /etc/fstab looks fine from what I can tell /dev/VolGroup00/LogVol01 swap swap defaults 0 0 ...
0
votes
3answers
4k views

How does putting swap space on an SSD affect performance?

This is more of a generic question I'm interested in, rather than something I'm planning to use in production. If I got, saym a 40GB SSD drive and allocated the entire drive to be swap space leaving ...
3
votes
3answers
2k views

Identifying a process that leaks memory

On a linux server (Ubuntu Lucid), my used swap keeps growing by the hour on a server, and I'm having a hard time identifying which process is growing in swap. What tool can I use to monitor this?
1
vote
1answer
780 views

Problem with setting up partitions - encrypted swap partition won't mount

Here's the layout I have; I'm using Software RAID10, LVM, and Encryption: LVM VG vg0, LV main - 2.0 TB Linux device-mapper (linear) #1 2.0 TB K crypto (vg0-main_crypt) ...
0
votes
4answers
3k views

Server super slow, RAM & Swap 100% used, ClamAV problem?

My Ubuntu 10.04 server is down since this morning. When I restart it, I can use it for a couple of minutes then the RAM and Swap get full, and SSH doesn't answer. It seems ClamAV is part of the ...
2
votes
1answer
113 views

suspend process if number of hard page faults surpasses a given amount per second

Is there a way in linux to send a signal or otherwise install an handler to be called when a process surpasses a given rate of hard page faults per second? A simple sigstop would avoid many ...
3
votes
4answers
1k views

Running swap on RAID10 or RAID5?

In follow-up to this previous question (and it's excellent answer), I am curious to know if running swap on a RAID5 might not be better than on a RAID10. My thinking is that you might lose a bit on ...
0
votes
1answer
1k views

What do the output values of dstat command mean when monitoring IO?

I am monitoring the IO and SWAP usage of a process in my backup server. I executed dstat -rs 5 and this was an example output: --io/total- ----swap--- read writ| used free 92.0 57.3 |3228k 514M ...
0
votes
2answers
243 views

Moving/Adding Additional Swap Location - Redhat 5

OK, here's what's going on. I've got a RedHat 5 server with a swap partition (/dev/sda3) that's 3GB. For some reason swap memory is still being taken up on / (/dev/sda2), and fills up the drive on ...
3
votes
2answers
712 views

Linux OOM disk I/O. Also: swap, what is it good for?

I'm having problems with the OOM killer on one of my Linux (2.6.37) installs. The computer has 4GB of memory which I sometimes utilize fully. In those cases, I expect the OOM handler to come in and ...
0
votes
2answers
350 views

linux + swap definition

how to decrease the Priority to 1 in place of 2 as described below? swapon -s Filename Type Size Used Priority dev/cciss/c0d0p6 ...
0
votes
1answer
375 views

LINUX + red hat + How to define swap on disk partition: /dev/cciss/c0d0p6

How to define swap (8G usage) on disk partition: /dev/cciss/c0d0p6 ( i have Linux red hat 5.3) for example: in my machine I not have swap definition Swap: 0 0 0 the ...
0
votes
2answers
376 views

Memory is available, but swap gets full over time

On a small VPS of mine, I have enough free memory for the things that are running there (as in the log below), but every once in a while, when I run free -m, I see all the swap is taken up. What ...
10
votes
6answers
9k views

SSD for swap on Ubuntu server

Currently I am reading SSD reviews and I wonder how much exactly I will benefit if I move the 24 GB swap from 7200rpm HDD to SSD. Does anyone implemented swap space on SSD? Is this generally good ...
1
vote
1answer
791 views

Where is the ESX Swap file in ESX 4.1i installed on SD cards?

Where is the ESX swap file located? I have installed ESXi 4.1 on a pair of mirrored SD coards, which came with the Dell server. ESXi runs really quickly, but with no local disks apart from the SD ...
1
vote
1answer
170 views

Exchange 2003 dial-tone with repaired database

After extensive Exchange 2003 DB corruption, we have set a dial-tone as emergency means of service for our users, then began restoring latest back-up to a recovery group, in parallel with fixing the ...
2
votes
1answer
953 views

Too much memory being swapped out, while cache uses it all on Centos 5.4

I've set swappiness on my DB server to zero, but during a large sort operation the swap space used grew even as the cache was still using a lot of memory, and then cache grew but swap was left alone. ...
0
votes
1answer
1k views

AIX swap usage shows ~20%, not even close to maximum load

I got an alarm that my swap usage was up to 80%, which turned to be a fact when I checked topas. The problems I've found were: 1) Looking into a vmstat 5 10, I found lots of PIs with 0 SRs. How's ...
4
votes
3answers
2k views

Do I need SWAP on my server?

I have a particular server : 50GB SSD for the OS (CentOS) , 128GB of RAM and 320GB SSD for MySQL. I'm wondering if I really need SWAP? I often read that 2GB is good even with lots of RAM. This ...
41
votes
4answers
18k views

Why don't EC2 ubuntu images have swap?

I started a couple servers on EC2 and they don't have swap. Am I doing something wrong or is it that the machines just don't have any?