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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Centos 6.5 only using 24GB/48GB of memory

I recently installed an additional 32GB of memory in my Dell PowerEdge R900 home virtual machine server. Memory check passed and I booted into CentOS. When I opened the Virtual machine manager and ...
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1answer
301 views

How do you track memory usage in a ksh93 script

We have a number of ksh scripts that run forever (inside a while loop), or at least until a shutdown event is delivered to them. We had a project where these scripts where converted to ksh93 (and ...
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934 views

Discrepancy between reported used memory and sum of application memory usage

I'm running a desktop system that quite regularly suffers from lack of memory, this prompted me to investigate what causes the issue in the first place. Problem is, there's no single process that ...
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3answers
603 views

On system memory… specifically the difference between `tmpfs,` `shm,` and `hugepages…`

I've been curious lately about the various Linux kernel memory based filesystems. Note: As far as I'm concerned, the questions below should be considered more or less optional when compared with a ...
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1answer
5 views

Fedora 20 memory.limit_in_bytes not working

Fedora 29 (kernel 3.15.10-201.fc20.x86_64) This worked in F19. I'm trying to use cgroups to limit memory usage for some apps that are prone to misbehaviour, and I'm encountering problems. I'm ...
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1answer
495 views

Can I use pmap to find out Memory utilization?

I want to measure memory utilization of my Apache Server. Can I use the pmap command and pass all the process IDs of httpd and take that as total utilization? pmap PID1 PID2 .... It seems that pmap ...
0
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1answer
368 views

Java/malloc memory corruption error when running SDK Android Manager

I want to install Android SDK, so I manually installed Java JDK 7u51, downloaded SDK ADT bundle for Linux x64, and tried to run it. When I run android, the SDK manager windows hangs halfway through ...
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20 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? ...
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2answers
87 views

How can I force bash to deallocate a brace expanded variable without name?

For benchmarking, I ran the command: for i in {1..100000000}; do echo "$i" line >> file done Bash expanded the braces and stored the list 1 2 3 4 5 6 ... 100000000 in memory. I thought ...
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1answer
347 views

Does sync command remove the dirty cache in the memory?

I am aware that sync command flushes the dirty cache into disk. I have run free command first, then sync, and then free again. The result of latter free command shows more free memory available than ...
2
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1answer
34 views

Find something that is occupying lots of memory and not visible in `ps` or similar

I have a VM that's having memory issues. One of the tasks I'd like to run in it is crashing with out-of-memory errors. However, when it crashes, the system still stays memory starved. I'm not sure if ...
2
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1answer
44 views

Dirty in /proc/meminfo for dd

I read from here that the below command gives me the amount of data that needs to be written to the disk. grep ^Dirty /proc/meminfo It particularly says Ever ask yourself "How much data would be ...
2
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2answers
421 views

Measuring CPU and Memory per user to distribute “cost” of a server

How should I implement approximately correct per-user monitoring on a server? I want a way to split the cost of a server between the users based on their usage. On newer machines (RHEL6) I would use ...
2
votes
2answers
1k views

How to reduce ClamAV memory usage?

I'm running a Ubuntu based web server (Apache, MySQL) on a 512MB VPS. This is more than sufficient for the website it is running (small forum). As I wanted to add some protection against viruses I ...
4
votes
1answer
52 views

How OOM killer decides which process to kill first?

This answer explains the actions taken by the kernel when an OOM situation is encountered based on the value of sysctl vm.overcommit_memory. When overcommit_memory is set to 0 or 1, overcommit is ...
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1answer
20 views

RHEL 5 Server running with 8 core. Load is always 0 or 1. but RAM (8GB) always occupied

I am seeing load is 0 or 1 since a few weeks on my RHEL5 server with 8 cores. But RAM always fully occupied. I am trying to debug the issue. How can we diagnose where memory is going?
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2answers
77 views

How to increase the memory used by Java in linux?

I have a program Vuze that is written in Java, which I use to download very large files, and I'm having a problem with it. I need to increase the amount of memory it uses. I've followed the directions ...
4
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1answer
389 views

Is it possible to find the physical address range of a DIMM?

I note that SMBios Type 20 would help here, but it's optional as of version 2.5 (2006-09-05) pp. 25, L796, and pp. 131, whereas types 16, 17 and 19 are mandatory, but don't quite help. Physical ...
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3answers
740 views

Linux / JVM - OutOfMemoryError: unable to create new native thread

I have a memory problem with a Linux server (CentOS). It is a VM. Below is the context. It has 70Gb of RAM. There are 2 tomcat running on it. One tomcat is given a heap of 13Gb and the other one a ...
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4answers
37k views

Limit memory usage for a single Linux process

I'm running pdftoppm to convert a user-provided PDF into a 300DPI image. This works great, except if the user provides an PDF with a very large page size. pdftoppm will allocate enough memory to ...
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1answer
19 views

Memory usage stays high after compilation jobs

I am operating a small Linux VM with 1Gb of RAM. It is a fairly typical LAMP setup which takes about 16% of memory on normal usage I used the box to compile stuff yesterday, the memory went up to 60% ...
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Reserve fixed RAM memory region as a block device ( with a given start physical address)

There have been a lot of questions about RAM Disks and I am aware of ramfs and tmpfs which allow the use of ram as a block device. However my interest is in using a fixed memory address range as a ...
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25 views

how to limit dma address to specific range in linux kernel?

I want to limit the dma address the device can access to 0x0100_0000~0x03ff_ffff. But I don't know how to set the dma_mask and coherent_dma_mask. It's easy to set the "dma mask" for a range start ...
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2answers
248 views

How to compare usage of memory by Window Managers?

I'd like to test a few window managers to see which of them takes less memory and CPU in certain time period (so is better choice for older computers). I'd like to make the tests myself (not to read a ...
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0answers
30 views

What is being cached?

I have an embedded system with a low amount of memory. The system has allocation issues. Maybe due to fragmentation: Memory allocation issue on NOMMU? The platform is a NOMMU platform and so I suspect ...
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0answers
10 views

Evaluating uncorrectable ECC errors and fallback methods [migrated]

I run a server which has just experienced an error I've not encountered before. It emitted a few beeps, rebooted, and got stuck at the startup screen (the part where the bios shows its logo and begins ...
2
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2answers
77 views

find out the memory allocated for a particular process in ubuntu

Could anyone please tell me how to find out the memory allocated for a particular process in ubuntu?
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0answers
54 views

Swap appears to not be in use

(I am currently using Ubuntu 14.04 LTS, GNOME environment) tl;dr How can I force more memory swapping (swappiness already at 100)? I have recently been experiencing a lot of system freezes/crashes. ...
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3answers
59 views

Lots of free memory, but Java won't start (SunOS 5.10)

vmstat gives: swap free 37489684 110178592 Still I have issues, while trying to run Java process with 10g heap: > java -Xmx10g -Xms10g -d64 HelloWorldApp Error occurred during ...
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1answer
25 views

Reserve memory for a program

Is it at all possible to set aside say 50MB of memory so that in an emergency where something uses all my memory or loads the CPU I could open a terminal, find the offending process, and kill it?
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3answers
5k views

How to get free memory on AIX?

How can I see the free memory on an AIX? There is no free -m under it. AIX oslevel: 6100-03-03-0943
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2answers
53 views

Memory allocation for sparse array in awk

I have searched but didnt reach to any conclusion that when i defined an sparse array does it reserve all the contiguous memory upto maximum index or it allocate the memory at that particular index ...
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6answers
3k views

Is there a tool that allows logging of memory usage?

I want to monitor memory usage of a process, and I want this data to be logged. Does such a tool exist?
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4answers
8k views

How to display meminfo in megabytes in top?

Sometimes it is not comfortable to see meminfo in kilobytes while you have several gigs of RAM. In Linux it looks like that: And here is how it looks in Mac OS X: Is there a way to display ...
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0answers
37 views

Inexplicable high memory usage (apparently not caused by programs, buffers, cache, or slab cache)

I've got a server that claims 1.7 of its 2 GB of RAM are used, but the combined memory usage of the running processes doesn't come anywhere near that figure: $ free -m total used ...
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1answer
8k views

How to find Heap memory of a running process? [duplicate]

I would like to know how to find the heap memory of a process that is running in the background. Is there any command that allows such?
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2answers
57 views

Use/See whole the flash memory space

When we bought a N Giga Byte flash memory, the free space that the OS provide for us, is less than N GigaBytes. For example, for a 2 GB flash memory, total space that we can use, is 1.86 GB. As far ...
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0answers
19 views

Is there anything in RHEL 6.5 that would affect I/O speed for something <24K vs >24K?

Generally, transactions for my app of setting and getting data internally are measured in a couple of millis. However, over 24K in size, that time can jump to just over 100 millis. Is there anything ...
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2answers
1k views

Defragging RAM / OOM failure

This question is fairly lengthy, so I'll ask the questions at the top and then go through my method of coming to the questions: Did (Busybox based) rm not execute because there wasn't enough ...
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1answer
47 views

Fastest and Safest way to increase Swap Space on Scientific Linux

Memory Swap Ratio Company System Today, a monitoring system indicated that one of the systems in the company has run out of memory. Executing htop on this system indicated that the Memory was nearly ...
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2answers
91 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 ...
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1answer
34 views

How to prevent certain memory location to be accessed [duplicate]

I have 2 corrupted RAM module, on offset: 46xx MB and 13xxx MB (from memtest on boot) How to prevent Linux to access/alloc/read/write into those offset? Here's the result of memtester on ~1000 MB to ...
0
votes
1answer
33 views

How can I tell if lack of memory is causing these crashes?

I have a tornado web server running a flask application that connects to a postgres 9.3 database on an ubuntu 12.04 box. The application has been crashing intermittently and I am trying to understand ...
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1answer
75 views

Real vs Actual memory in Xymon/Hobbit

What is the difference between real and actual memory usage in xymon ?
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1answer
66 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?
0
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2answers
49 views

What are the positions in `free` called?

I am trying to compare the output of free with the output of sar -r: # sar -r 12:00:01 AM kbmemfree kbmemused %memused kbbuffers kbcached kbcommit %commit 12:10:01 AM 629756 65293976 ...
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3answers
3k views

What does the vm.swappiness parameter really control?

Per the kernel documentation: This control is used to define how aggressive the kernel will swap memory pages. Higher values will increase aggressiveness, lower values decrease the amount of swap. ...
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votes
4answers
212 views

How much RAM needed for preventing use swap?

At my system always available some "Free" and "Inactive" memory, but sometimes system move couple megabytes to swap. Per night it maybe around 100MB, but for a few days in swap could be more than ...
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0answers
30 views

Why does Android crash when stressed on Memory where as GNU-Linux keeps running?

I have two devices, an Android phone with an eGlibC stack running side by side with Bionic, and an old HP tower with Debian. My HP tower has 512 MB of RAM. My phone has 2GB of RAM. I run top on ...
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4answers
122 views

What is using memory? [closed]

According to htop and free, the machine I'm looking at is currently at 6631 / 11907 MB of RAM. That's more or less half of the RAM available. However when I sort top or htop by MEM%, the most memory ...