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1answer
25 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
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0answers
50 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
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1answer
26 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 ...
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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
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3answers
4k 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 ...
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1answer
40 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
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0answers
54 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
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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 ...
45
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2answers
71k 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?
2
votes
1answer
32 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
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1answer
76 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
917 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?
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0answers
125 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
58 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
580 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
119 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
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2answers
874 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 ...
10
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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 ...
5
votes
1answer
123 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
117 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
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0answers
30 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
447 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 ...
3
votes
4answers
20k 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
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1answer
92 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
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1answer
44 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
110 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
130 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
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0answers
16 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
32 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
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0answers
274 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. ...
3
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2answers
2k 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
153 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
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0answers
107 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
73 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
386 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
195 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
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0answers
129 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 ...
1
vote
4answers
10k 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
82 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
361 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
134 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 ...
3
votes
1answer
146 views

How to limit a user's RAM on Ubuntu? [duplicate]

I currently have a "friend" that has an account on my dedicated server which is running Ubuntu. Not getting into specifics, but he said he will use ~2gb max and he's using ~10gb. On to the question. ...
2
votes
3answers
543 views

Memory Mapping Linux 3+ kernel

Can some one help me understand how memory mapping is done Gone through this Why does Linux show both more and less memory than I physically have installed? but still i am not able to understand ...
1
vote
1answer
84 views

CPU and RAM monitorization by parent id

I'm trying to monitor the CPU and RAM usage (in % of total for example) of a given process wich may spawn several processes. The parent process is /bin/rscw so I get its pid by ppid_bl=$(ps -ef | ...
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0answers
167 views

Second RAM module is not shown in `free` in Manjaro

I have two RAM modules (8 GB each) but there is only one shown in free. I hope that following info will help you to locate the problem and find a solution: $ uname -srvmo Linux 3.10.27-1-MANJARO #1 ...
14
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1answer
3k views

Loading of shared libraries and RAM usage

I'm wondering about the way Linux manages shared libraries. (actually I'm talking about Maemo Fremantle, a Debian-based distro released in 2009 running on 256MB RAM). Let's assume we have two ...
1
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0answers
182 views

weird problem with 64 bit install and memory

I have a laptop with 8gb of RAM in two 4Gb slots, the processor is 64 bit compatible. However when I try to install 64 bit version of Linux (I tried, mint, arch, manjaro), it refuses to load the ...
4
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1answer
3k views

How to view RAM's SPD / timings table?

In Linux Mint, how to get the same information presented in the lower half of the below picture? Output by CPU-Z in Windows: What I've tried: Running CPU-Z 1.66 in Wine as Windows 95, 98 and XP. ...