In computing, memory refers to the state information of a computing system, as it is kept active in some physical structure.

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How to troubleshoot High VIRT and RES memory on a Standby Server

We currently run TIBCO EMS on our RHEL6 servers, it is Active-Passive setup, for some reason we are seeing a really high VIRT and RES usage by the standby instance (approx 198GB). The application (...
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tstime and memory usage

So I am interested in measuring the high-water memory usage of a process. I would love to be able to use tstime but am having troubles figuring it out. Does it work in Unix? When I go to https://...
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417 views

Memory usage of an infinitely looping shell script

So, I have a shell script for updating a MySQL database that looks something like this: #!/bin/sh mysql -h "localhost" -u "root" "-p********" "database" < "update.sql" sleep 5 sh $0 It sleeps ...
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2answers
355 views

Physical Address Extension - how do virtual addresses work?

I'm running Debian Linux. uname -m says i686 which means 32-bit architecture machine with pae flag enabled. getconf LONG_BIT is 32. Installed RAM capacity is 6GB. My /proc/cpuinfo has an entry ...
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Why process is killed while a lot of memory is free?

I am running a python script in ipython. This script will take about 8GB RAM. The system has more than 80 GB free RAM but the swap is nearly 0. My script was killed after it runned for a while. I want ...
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44 views

Can I trust in memory information of dmicode?

I want to buy 16gb memory for my notebook. I ran dmicode and found this information: Handle 0x0005, DMI type 5, 20 bytes Memory Controller Information Error Detecting Method: None ...
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43 views

/proc filesystem - getting useful information

I'm trying to understand the values in /proc/PID/status. I want to calculate cpu% & mem% used by PID, similar to top bash command. For Memory percentage usage I can do the following (correct me ...
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1answer
157 views

Resource (CPU time and memory) limitation and termination of a process upon violation in Linux

The problem: Given a process, limit the resources it and its child-processes can use. I.e. set CPU time and virtual memory quotas. When the process group exceeds one of the limits, terminate it, ...
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140 views

What does Linux spend memory on other than userland, caches and slab?

I have a system with 1 GB of physical RAM. Right now, free shows the following memory usage: total used free shared buffers cached Mem: 1026360 863660 ...
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49 views

Which process wrote to which memory address? [closed]

Recently, I've been seeing a wide variety of memory-related crashes at work (C++ applications on Ubuntu 14.04). Our applications use a properietary third party library to interface with real time data ...
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1answer
180 views

How to find the page size of physical memories from userspace?

I want to understand the page size, sector size, block size (if applicable) of a usb flash drive. Is there a way for me to inspect those with Ubuntu? mount /dev/sda1 /mnt ? umount /dev/sda1 Edit ...
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Is High Virtual Memory usage a problem or may cause problems?

In our server, we have a python based code that listen ports. The amount of Virtual Memory it uses is increased greatly with time Like: USER PID %CPU %MEM VSZ RSS TTY STAT ...
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Do I need swap space if I have more than enough amount of RAM?

From what I understand, the purpose of a swap partition in Linux is to free up some "not as frequently accessed" information from RAM and move it to a specific partition on your harddrive (at the cost ...
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1answer
152 views

How do I forbid access to physical memory in Linux?

I'm on an embedded system (Zynq from Xilinx. It uses ARMv7, Cortex-A9), and running Linux. I need to ensure that no access to a certain physical memory range is ever made, either accidentally by the ...
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93 views

What is kswapd_low_wmark_hit_quickly from /proc/vmstat

What does this parameter mean? # cat /proc/vmstat | grep low kswapd_low_wmark_hit_quickly 2
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1answer
84 views

Substantial portion of memory used is not accounted for by user processes

I recently installed a copy of Ubuntu Server 14.04.2 LTS on a cluster. All appears to be working fine, but a large portion (around half) of our total available RAM is being used. I.e., when I run ...
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309 views

Does anyone actually use and benefit from transparent huge pages?

I've been struggling with transparent huge pages performance issues of late, and noticed many database systems recommend turning it off. I am talking Oracle, Postgresql, MySQL, Cassandra, NuoDB, Redis,...
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2answers
1k views

How to mount a dd-image which was created via fmem (memory dump tool)

I'm quite new to Linux. I've used the tool fmem for creating a memory dump dd-file. That works fine. But how can I access this image? I've tried it with mount but it says I have to specify a ...
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2answers
133 views

Sum the memory usages of all the processes of a program?

How can we sum the memory usages of all the processes of a program? For example, I have opened many Chrome tabs for webpages, and each tab runs a different process. How can I get the total sum of ...
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331 views

Process Being Killed due to low swap

I'm running a python (2.7) script on mac osx yosemite. The script is fairly computationally intensive, certainly bumping up against my machine's RAM limitations. The computer crashes and restarts ...
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2answers
183 views

What unit is used for the memory values from top command in Linux?

I have the following snippet shown as my top command output. One real quick question here being, the values of Mem are shown in what granularity? Are they the number of bytes? Mem: 8191488k total, ...
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2answers
333 views

Linux Mint 64 bit eating ram

I have a Mint 17.1 install. It has 2x2Gb memory sticks. I have verified this with sudo dmidecode --type memory. My problem is that I don't see all the memory I expect.I would expect 4194304 kB. (i.e. ...
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Memory utiization

I use free -m to check memory status. In this pic we see total used & memory. I want the result in %. Like Used memory - total memory x by 100. And whenever I want to check the memory status, it ...
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3answers
3k views

How to calculate the memory consumed by a “C” program in linux

I have written two C programmes one is using function pointer, and the other without function pointer. Now i want to know the memory consumed by the two programmes , to see how memory can ...
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365 views

Java process gets killed frequently by OOM - Killer on upgraded hardware

I am running solr on an Ubuntu server along with 4 other java processes. Current index size is 30 GB. My solr process gets killed frequently in few hours. It clearly mentions that its an OOM killer. I ...
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154 views

/dev/mapper/vg00-var maxing out

Over the past few years we have had multiple Linux servers have the same problem time and time again: our /dev/mapper/vg00-var folder maxes out at 100%, which means all sites on the server die. We ...
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2answers
323 views

CRON Job To Execute Command On Low Memory

I have a situation where I may need to execute an SAP command line tool hdbsql when memory gets too low (to help clean out the HANA table cache). I'm not well versed in Unix/Linux, and was wondering ...
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206 views

Kill the process and restart server when memory is exceeded - bash and cron

I have a site on webfaction, using django and python. However, I have problem with memory. The problem arises, because I use external library, that can run forever (consuming much time and memory). ...
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How to recover data after memory module errors [duplicate]

My linux PC has suffered the occasional application crash, desktop crash, and kernal panic over the last few months. I also started noticing error dialogs on login, and some parts of the desktop do ...
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1answer
180 views

Linux doesn't drop FS Caches. Instead Memory starts Swapping

I'm quite confused about this behaviour of linux memory caching. total used free shared buffers cached Mem: 15953 14188 1765 64 ...
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2answers
1k views

How to enable swap accounting for memory cgroup in Archlinux?

On my Archlinux box I want to limit some applications to a smaller amount of memory using cgroups. Since I use swap, I need to account memory+swap. How can I enable swap accounting?
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2answers
280 views

What proportion of memory does the Linux kernel use of the installed RAM?

I'm developing a compute cluster and I'm trying to determine the maximum amount of RAM I can give to a single process. On a machine with 16GB of ram, the answer is that I can allocate (and touch) ...
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what does mean by HardwareCorrupted, DirectMap4k, DirectMap2M fields in “/proc/meminfo” file of Linux?

I am looking for description of following terms: HardwareCorrupted, DirectMap4k, DirectMap2M fields in "/proc/meminfo" file of Linux. I could find the following description for the fields from ...
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4answers
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Memory consumption Fail2Ban CentOS

Fail2Ban is using a huge amount of memory on my system (1.2 GB). There are several articles which describe how to reduce it. Below is an example for Debian. append the 1ulimit1 command to /etc/...
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54 views

Who are the Linux Memory “subsystem” developers?

After an hour of googling, I still cannot find Linux Memory subsystem developers contact e-mail. Question: Where is the webpage that shows who develops the Linux kernel, specifically the Memory "...
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1answer
1k views

git Fatal: Out of memory, malloc failed on branch push

I know this has been asked a lot but I did not manage to get any solution to solve my problem. My coworker assigned me on a new project. The application is hosted on test Debian server with git ...
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1answer
123 views

What is kernel memory and user memory? (question about the term kernel page and the page cache)

Today, I have read through some documents about file system (http://tekrants.me/2014/07/14/linux-file-system-write/). And the term kernel page is mentioned several times in this article. I am now ...
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269 views

How to read the output of the show-memory-usage SysRq?

I couldn’t find any (recent) documentation on reading the output of the show-memory-usage SysRq (Alt+SysRq+m). So what can one learn from looking at it? Here is an example output form my box (Kernel ...
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2answers
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Utility which gives line from /proc/id/maps by specific address

Is there an utility that gives me specific line from /proc/id/maps when given specific address from this process? For example when given 0x7fb4a84f6008 it returns: 7fb4a84f6000-7fb4a84fd000 r-xp ...
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Which parts of Memory can Swap Support

For this question, "swap" does not include RAM and only refers to the configured space on the disk. According to, http://www.ualberta.ca/CNS/RESEARCH/LinuxClusters/mem.html, a program's memory usage ...
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1answer
97 views

Can swap space accomodate single process?

From what I understand, the swap space can be used to swap out inactive processes to free up memory. But can a single process take advantage of swap space? For example, if my system has little memory, ...
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7answers
13k views

Is there a way to limit the amount of memory a particular process can use in Unix? [duplicate]

I need to test a process for memory management. I do not have the source, so I need to do all the testing from the OS side. I want to be able to say something like limitmemory 400k -p <pid> ...
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268 views

Ubuntu 14.04 using 100% swap space, with more than 40GB free memory, why?

I'm a bit at a loss trying to figure out why this would be the case. Can anyone provide some helpful ideas on troubleshooting this? $ free -m total used free shared ...
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104 views

How to check if allocated memory was freed?

Does anyone know which command I need to enter on the terminal, so I can check whether all allocated memory was successfully freed?
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1answer
114 views

What memory is not used by processes and freed by `echo 3 > /proc/sys/vm/drop_caches`?

Without programs open, my computer uses about 512M of memory. Yesterday, I had nothing open, yet 2 GB of mem use (used - cache = 2153): total used free shared buffers ...
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420 views

AIX Memory Limits

I cannot find these numbers anywhere on the IBM Web site or even random blogs that Google finds. Questions What is the maximum physical memory size a POWER7 CPU supports? What is the maximum ...
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268 views

How to track down the source of I/O spikes?

I am using Linux as a desktop, and keep getting seemingly random I/O Spikes. The machine becomes unusably slow. At first I thought it was just that I don't have enough memory. But looking at the ...
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110 views

How are the values represented with the “free” command

I am interested in the totals of the 3 lines. Specifcally, if the "used" values can be counted as what's going on in real time, or if that's just a running total since the OS was started? How does ...
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4answers
2k views

Making Linux read swap back into memory

The Linux kernel swaps out most pages from memory when I run an application that uses most of the 16GB of physical memory. After the application finishes every action (typing commands, switching ...
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How can I find how much RAM are VMware Player VMs using on Linux?

I am running Debian Jessie 64-bit on a computer with 8 GB of RAM. This is my memory usage according to htop(with a fairly large Firefox session) before starting a guest VM that has 4 GB allocated. ...