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6
votes
2answers
61 views

Besides cache, what does the Linux kernel use significant amounts of memory for?

My computer feels really sluggish. According to free, I have only ~200M RAM left and more than a gigabyte had to be swapped out. I know that it is good if memory is used for caching but this looks ...
1
vote
0answers
16 views

The command “dmidecode -t 17 | grep Size” showing in CentOS release 6.5 (Final).

Recently I upgraded the system(Dell 720) RAM 8 to 16 GB(4*2[new ram]), but it is still showing old amount of RAM(ie 8GB). Please help me, If I need to install driver(module). Kindly Let me know all ...
53
votes
3answers
93k views

How do you empty the buffers and cache on a Linux system?

Prior to doing some benchmarking work how would one free up the memory (RAM) that the Linux Kernel is consuming for its buffers and cache?
3
votes
1answer
60 views

Why am I missing 2% of my ram

I am running grep MemTotal /proc/meminfo to determine the RAM installed on a system, however instead of reporting a number corresponding to an even number of GB, it is slightly off. I.e. on my 64 GB ...
0
votes
0answers
5 views

Boosting responsivness of krunner or yakuake

It sometimes takes up to 20 seconds for krunner (kde application launcher, i actually use it with XFCE) to show up when my pc is under heavy load. How can i upgrade its responsivness (to, for example ...
11
votes
2answers
2k views

Is using a read only root file system a good idea for embedded setup?

I have been tasked with running Linux as an operating system on an embedded device. The target has an x86 processor and has 8 GB CompactFlash device for storage. I have managed to use buildroot to ...
2
votes
3answers
100 views

Is there a linux OS that can be loaded entirely into RAM?

I have 32 GB of memory in my PC. This is more than enough for a linux OS. Is there an easy to use version of Linux (Ubuntu preferably) that can be booted via optical or USB disk and be run completely ...
0
votes
1answer
44 views

What desktop enviroment consumes fewer resources? [closed]

I want to install Mint in my laptop, but I'm undecided about which desktop environment I should use with it. Currently the available desktop environments the distribution offers are Cinnamon, MATE, ...
0
votes
0answers
16 views

Perform task on waking up from suspend

I have program that misbehaves when my pc wakes up from suspend to ram, it starts using up to 40% of processor time so i usually have to kill it manually. How can i set specific command (pkill in ...
1
vote
1answer
46 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 ...
1
vote
0answers
166 views

Booting Linux from RAM

I want to find a cross-distro solution for setting linux up to boot from RAM. What this involves in essence would be copying an existing installation of linux one way or another over to the RAM (to ...
0
votes
1answer
66 views

hpux: how much memory process eating?

I have found on web those two command line to see top 10 cpu and ram eating process ram echo " SZ PID RUSER COMMAND";UNIX95= ps -ef -o 'sz pid ruser args' |sort -nr|head -10 cpu echo " SZ PID ...
9
votes
2answers
2k views

How can I dump the full system memory?

After starting VirtualBox, the computer became sluggish and then hung completely due to OOM. Usually, OOM should be starting killing processes in order to free up some space, but this did not happen ...
7
votes
3answers
5k views

Why is the theoretical RAM limit for RHEL 6 128 TB and how is this determined?

I'm studying for RHCSA and am confused by a statement I came across in some training material: There is no practical maximum RAM, as theoretically, you could run 128 TB of RAM on RHEL 6. But ...
-2
votes
1answer
55 views

How much RAM and CPU for a NTP server? [closed]

As a side project, I am thinking about adding a NTP server to pool.ntp.org. I would like to use CentOS basic, but how much RAM and CPU should I assign to a machine that will only be running ntpd (plus ...
2
votes
0answers
57 views

How can I let high priority processes continue when low priority processes are causing free memory to be low

Ok I'm not sure if this is the correct place to post this. It is more of a 'why not' question than a 'how to' one (assumption is that it isn't/can't be done). Why don't we allow RAM to be partitioned ...
6
votes
2answers
7k views

Move /tmp to RAM

I am trying to move /tmp to RAM and obey good practice: /var/tmp should NOT be placed in tmpfs, as it must survive reboots not mount /tmp as a stand-alone tmpfs, but rely on /dev/shm or /run/shm ...
2
votes
1answer
36 views

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 ...
0
votes
1answer
99 views

What is the difference between MAC OS X “Virtual Memory” and Linux/Unix Swap? [duplicate]

I would like to understand the difference of MAC OS X "Virtual Memory" and Linux/Unix Swap. I ask this because I observed that MAC OS X "Virtual Memory" seems to work way more efficient (in desktop ...
4
votes
2answers
1k views

How to benchmark RAM memory with a Linux Distro?

I' ve just bought new RAM and I'd like to benchmark and compare with my old. How can I do that?
1
vote
0answers
160 views

Unable to figure out what hogs my RAM [SOLVED] [closed]

Solution: It was file buffers causing the used RAM that didn't show up in htop. To resolve this issue I used the command sync && echo 3 | sudo tee /proc/sys/vm/drop_caches OP: I have a VM ...
1
vote
1answer
74 views

When the RAM is used up, what will happen?

When I ran ImageMagick's convert to convert and combine image files into a pdf file, it will create 10GB temporary dirs and files in /tmp. I am not sure if it did that all the time, or because my ...
1
vote
0answers
13 views

How to interpret numerous processes with exact same RAM usage [duplicate]

I have a VM that processes files, parses the information and saves it to a database. I've been monitoring the resource usage and noticed /usr/sbin/console-kit-daemon --no-daemon.. Below you see a ...
1
vote
3answers
1k views

Is there any way to know the size of L1, L2, L3 cache and RAM in ubuntu?

Is there any way to know the size of L1, L2, L3 caches and RAM in Ubuntu?
1
vote
1answer
137 views

CentOS 6.5 : machine with more that 1 TB RAM => “no free pages available” on boot

I have a upgraded a server with more than 1 TB of RAM, and it is unable to boot. With 768GB of RAM all is working fine. I got the following message : Trying to allocate 1005 pages for VMLINUZ. ...
1
vote
2answers
1k views

Using only 3.3GB but I have 8GB RAM even on Ubuntu 14.04 64bit

I have 2x 4GB(8GB) RAM installed on my motherboard and BIOS/UEFI can confirm it, but on Ubuntu 14.04 64bit only has 3424776kB or 3.266120911GB. uname -a returns: 3.13.0-36-generic #63-Ubuntu SMP Wed ...
5
votes
1answer
143 views

Where has my RAM gone & how to interpret atop's memory output?

For a while, I encounter RAM-shortages on my Debian webserver (VPS/virtual machine). This would not be unusual, if they happend on a regular basis. But they do not. Here's a chart from Munin: ...
1
vote
1answer
161 views

file access time after loading file into the cache

I read from here that I could load file into RAM for faster accessing using the below command. cat filename > /dev/null However, I wanted to test if the above statement is really true. So, I ...
0
votes
0answers
39 views

How fast is a process reading/writting virtual memory?

So, we have top, htop, iotop, iostat, vmstat, etc, to measure many different things on Linux, but how can one measure how much MB/s a process is reading and writting to/from RAM, i.e., virtual memory? ...
0
votes
1answer
460 views

swappiness and RAM usage

Been going through this topic - http://askubuntu.com/questions/157793/why-is-swap-being-used-even-though-i-have-plenty-of-free-ram. Turned down swappiness to 10 and then to 0 but my installation is ...
5
votes
4answers
24k views

Java “Could not reserve enough space for object heap” even though there is enough RAM

I am currently having some issues running Java. It won't start because of heap issues. But I have more than 9 GB Ram free (or even 16 GB if you assumed the cache would be empty). This is the error I ...
2
votes
1answer
110 views

Memory Usage in Linux [duplicate]

How to setup limit for process to memory usage? Similar to open files limit in /etc/security/limits.conf: ubuntu soft nofile 4096 ubuntu hard nofile 8192 ...
0
votes
1answer
47 views

What dev folder allows you tell the OS to cache something?

Someone told me that there is a sub folder off of dev that basically allows you to tell the OS to keep the contents of that folder cached in RAM. So if I put some files & directories in ...
0
votes
1answer
127 views

Arch linux weird ram issues

I installed Arch linux (I have reinstalled it a couple of times, actually, in the past 3 months, just to get to know it better). My problem is, that I have 4GB RAM, and as soon as my free RAM hits ...
1
vote
2answers
148 views

Why does Linux only see 3832MB of my 4096MB of RAM?

I am setting up a lot of 64-bit RedHat VMs (VMware vSphere) for our development department in my company. Most of them start with 4096MB of RAM, but Linux only seems to recognize 3832MB. Can anyone ...
0
votes
0answers
18 views

how to find where buffers/cache are and how to clean them up? [duplicate]

I want to create 20gb ram disk for ANSYS to work in yet on free -g I see: And personally I have not created any ram drives yet. So I wonder how to maximize avaliable ram: how to locate what is using ...
0
votes
1answer
39 views

Virtualbox delete vm ram

If I delete a VM in VirtualBox, what happens with the RAM I used to create that VM? Is it freed?
0
votes
1answer
1k views

How to reduce chrome's virtual memory usage?

I am running a Debian Jessie and having memory issues when using Google Chrome I tried disabling extensions, disabling cache, flushing the cache, and disabling the web 3d rendering, but nothing ...
3
votes
0answers
281 views

My SMDK2416 (for s3c2416) kernel works on 64MRAM but crashed on 128M

I'm currently working on embedded arm linux with smdk2416(s3c2416) The kernel is working on the 64MRAM. Recently, I need to increase the RAM from 64M to 128MB with 64MB on bank0 and 64MB on bank1. ...
6
votes
2answers
3k views

How to tell whether RAM ECC is working?

I'm planning on getting some ECC RAM to replace the non-ECC RAM I currently have installed on my Asus M5A97 Pro motherboard (AMD 970 chipset, FX-6100 CPU). After I install the RAM, how do I tell ...
0
votes
1answer
189 views

should I reduce /dev/shm size?

I have a server wity 8 GB RAM Mem: Total 8031464 Used 5146344 Free 2885120 If I execute # df it always returns this tmpfs 4015732 0 4015732 0% /dev/shm What does it ...
1
vote
0answers
120 views

Swap on video ram in a VM

I have a very small VM running in a cloud with only 512 MB ram. I read, it is possible to use the video card as swap as descriped here: Graphics cards contain a lot of very fast RAM, typically ...
1
vote
1answer
86 views

Compress memory on low Ram VM

Is there a way to get out more out of your limited Ram on a VM? I have a VM running on a cloud hoster and try to optimize a quite low on RAM mashine. I heard, there is a way to compress parts in the ...
4
votes
1answer
438 views

Does tmpfs automatically resize when the amount RAM changes, and does it compete when there's multiple tmpfs?

If I have a tmpfs set to 50%, and later on I add or remove RAM, does tmpfs automatically adjust its partition size? Also what if I have multiple tmpfs each set at 50%. Do multiple tmpfs compete ...
5
votes
2answers
219 views

1GB huge page - Is writing occurring in 1GB chunks?

I'm trying to understand the relation between huge page size and how data is actually being written to RAM. What happens when a process uses a 1GB huge page - does writing occur in 1GB chunks? I ...
1
vote
0answers
134 views

Xeon Phi swap from host's tmpfs

I want to use swap on Xeon Phi (mic0) using RAM from the host On the host: # free -m total used free shared buffers cached Mem: 129022 60312 ...
2
votes
4answers
11k views

How to clean up the RAM memory that is being used as cache memory?

My processor is using a big part of my RAM memory as cache and I want to clean it up because of that; will it prejudice something?
0
votes
1answer
85 views

Take copy of RAM

How trivial is it to take a copy of the current state of a Live Linux Distro's RAM storage? I have had situations where it might be useful to debug what caused a problem with the OS, and if I had ...
6
votes
1answer
441 views

How to have Linux wipe/randomize/sanitize RAM at shutdown?

For mysterious reasons I still double boot sometimes into Windows. My problem is that I fear that information may leak because the RAM memory is accessible to Windows. (the Linux partitions are ...
3
votes
2answers
142 views

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 ...