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 run a process and find how much memory it uses? [duplicate]

I regularly use time to find out how long a process takes. Is there an equivalent command for memory? The usual ways to find out how much memory a process takes (ps,/proc/meminfo, etc.) work fine for ...
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40 views

Memory not used any more but still allocated

I have something kind of weird going on with memory. I have Ubuntu 14.04 servers with Zimbra 8.6 with kernel (for this one) 3.13.0-37-generic. But I have already seen the problem with other kernels. ...
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Get total memory size on sun os through kstat

I have sun os there Following commands are not available prtconf prtdiag psrinfo The only command which is working is kstat. Can any one please help me on finding the total memory size using only ...
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2answers
19 views

How to improve Solaris Server Configuration [on hold]

As a programmer I have limited knowledge of the ins and outs of Hardware configuration. I've been tasked with assisting in server tuning. I understand tuning a server for peek performance varies per ...
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What is the difference between mem usable and mem free? [duplicate]

What is the difference between usable memory and free memory ?
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44 views

Keep a process in RAM (prevent it from swapping)

I want to keep a process in RAM. It should never go into swap. Is this possible? The process is a Java program. I'm running CentoS 7.
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How to mmap file w/ HUGE_PAGES to specific memory location (via “memmap=4G$4G”)

Presently working: Device driver to mmap to specific memory location (isolated by boot parameter "memmap=4G$4G") via the remap_pfn_range call. Desired solution: Same/similar outcome using 2M pages ...
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19 views

How does disabling data journalling speed up the file system?

How exactly does disabling journalling give a better performance in case of Linux (ext4)?
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59 views

Disk busy 101% all the time

I have an OpenNMS Linux server which is having poor disk performance. The machine is a EC2 inside a VPC. atop shows: iotop shows: How do I reduce the IO numbers and bring down the disk ...
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26 views

How to know what exactly is being written or which process is keeping my storage disk busy?

I have a server , which has gone rogue(not really), i ran nmon and saw that its Disk utilization is BAD, its 100% busy writing!! Here is the output : Can someone tell me what is keeping my disk ...
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25 views

How can I mount remove /dev/mem to local

This question is relate to this, but more general. Currently I mount remote root by sshfs sshfs -o sshfs_sync,sync_readdir,reconnect,follow_symlinks,direct_io,sync_read root@pi:/ pi /proc is ok, ...
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When interrupting a process, does a memory leak occur?

Lets say I created a program in c/c++, where I manually allocated some variables. Then while running the program, I send an interrupt signal (Ctrl-C). Are those variables freed from memory, or will ...
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51 views

free command output: gentoo (redhat?) vs debian

I noticed there is a difference between outputs of free command: On debian: $ free -h total used free shared buffers cached Mem: 4.0G 3.4G ...
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OOM Killer: Processes have a score of over a 1000

All top links when Googling for OOM score seem to indicate that the values must be between -1000 and 1000. I tried to verify that with a simple cat /proc/*/oom_score | sort -n | less and I ...
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Why does .text region of shared libraries is not flagged as VM_SHARED?

When I'm using shmem/mmap to share memory between processes I can see with pmap that it creates virtual memory area that marked as shared. Example: Address Kbytes RSS Dirty Mode ...
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How to calculate the amont of kernel memory allocation on Linux?

My system has 128GB physical memory. However, free -h said I have 125 G total memory. [root@rhel7 ~]# free -h total used free shared buff/cache available Mem: ...
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654 views

Finding the source of CoW page faults on OS X

I'm trying to find the source of CoW page faults in some C code on OS X. I would like to use the vminfo DTrace provider, but vminfo isn't available on OS X. On Linux, I can use SystemTap to print a ...
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39 views

How do you change the Hugepagesize?

How can I change the pagesize for Hugepages on Linux? I'd like to increase it to 4096 kB or 8192 kB. I'm working specifically with Centos and Amazon Linux. $ grep Hugepagesize /proc/meminfo ...
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29 views

-/+ buffers/cache & Swap

When should the usage of swap get started? or How do I know that my swap is being used? At least some times if not always, considering the default swappiness of 60 Also, why does free offer to omit ...
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vmstat -s command fields meaning, specially “pages paged in” vs “pages swapped in”

Most of the fields are understandable but can someone please explain me the difference between "pages paged in" and "pages swapped in"?. I'm pretty sure that swapping is when the entire process is ...
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525 views

awk memory leak?

Base on this I'm running the command < /dev/urandom hexdump -v -e '/1 "%u\n"' | awk '{ split("0,2,4,5,7,9,11,12",a,","); for (i = 0; i < 1; i+= 0.0001) printf("%08X\n", ...
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28 views

Eviction of Disk Cache in Memory

Say RAM is 100% used, some by disk-cache and some by applications. There is plenty of swap (on a hard disk available). If Linux decides to evict a page that contains application data, it would be ...
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44 views

How to log every memory access in linux of a single program? [closed]

I am trying to analyse the memory usage of a single program and need a list of every access the program made, so basically i need something like Valgrind but with a complete output.
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vm.swappines parameter influence on system without swap partition

I run across following definition of vm.swappines: The swappiness parameter controls the tendency of the kernel to move processes out of physical memory and onto the swap disk. So, if I have ...
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1answer
59 views

How to debug an Out of memory crash

Recently one of my CentOS6 server crashed because of an Out of memory Error: It seems to be related to the postgres database used by java web-applications (deployed on tomcat). But I cannot find ...
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108 views

Understanding and configuring Cache Memory

I have few questions about Cache Memory In my system "free -h" command gave me below output, total used free shared buff/cache available Mem: 7.6G 2.1G ...
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Gentoo Hardened eats 3 GB of memory after running for ~12 hours with very few processes running

I'm running Gentoo Hardened AMD64 using kernel 4.3.3-hardened-r4. With my system only running some basic daemons like wpa_supplicant, cron or DHCP, and with an X session with only Windowmaker, GKrellM ...
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Why do different instances of the same program use up different amounts of memory?

I simply started 5 instances of the default xterm, doing nothing in them at all. Looking at the output from htop, it appears that these instances use different amounts of RAM: VIRT RES ...
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Logging memory issues with Cron

I'm trying to log memory errors/issues using cron, however I'm still unsure how to do this. I'm new to cron, but I entered our system with it already using the tool. We've been having memory issues ...
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29 views

Why does OOM-killer sometimes fail to kill resource hogs?

If I type in my shell x=`yes`, eventually I will get cannot allocate 18446744071562067968 bytes (4295032832 bytes allocated) because yes tries to write into x forever until it runs out of memory. I ...
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51 views

Convert meminfo kB to bytes [duplicate]

To convert the readings in /proc/meminfo from "kB" to bytes, should I multiply by 1024, or 1000?
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33 views

What is difference between cached memory and used memory?

In my System Monitor panel applet in Linux Mint 17.3 Cinnamon, it shows me memory usage of used memory and cached memory combined, whereas in the system monitor application, it just shows used memory, ...
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C++ app. with mmap kills kernel? (kernel panic with mmap)

In my C++ program where intensive disk, network I/O and even CPU computation occur, I am using memory mapped region as an array. With very small data, it works fine. However when I ran the program ...
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What is the default memory allocation for shell process by linux

What is the default memory allocation for shell process by Linux , i mean is there any upper limit for shell process or any process.
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Memory leak on webserver

So I have lately been have some server performance issues. Currently we are running a Fedora server with 4GB and 160gb disk space. We are pretty much capping out the disk, with all of the files we ...
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81 views

How can I get the amount of available memory portably across distributions?

The standard files/tools that report memory seem to have different formats on different Linux distributions. For example, on Arch and Ubuntu. Arch $ free total used free ...
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52 views

Exceeding memory issues on server using PHP

PHP has memory limits set at a global level in the PHP.ini file. I also know that they can be configured at the local level. Our memory limit for a query is set to 132MB, but we keeping getting ...
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1answer
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Get current memory usage of a tmux session

As the title says. I need a way to the used memory of a current tmux session. I am not sure if that is even possible. I am using tmux to start multiple minecraft servers I'd like to know each servers ...
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why we need ram if we having swap memory? [closed]

In Linux we have a swap memory right. the system will use swap memory if ram memory is full.then what is require of RAM we can use directly swap memory.
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442 views

High memory usage but no process is using it

I run free -m on a debian VM running on Hyper-V: total used free shared buffers cached Mem: 10017 9475 541 147 34 909 ...
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43 views

Downsides of processes with high virtual size but low RAM and GPU memory use

I have noticed that some of my processes take a lot of virtual size in my computer. I understand that the virtual size of a process is the sum of memory it is actually using, memory it has mapped into ...
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1answer
29 views

How does OSX handle Out of Memory conditions?

Linux uses the OOM killer; what do Macs do?
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1answer
95 views

FDT relocated by U-Boot cannot be accessed by Linux (in highmem)

We run a customized version of U-Boot on an ARM-based embedded system and would like to load Linux 4.3 with a device tree blob. The system features 1GB of RAM of which the top 128MB are reserved for ...
5
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1answer
62 views

Is forcing an application to release some the allocated memory possible?

Ever since I came back to Firefox a year or so ago I have been facing the same issue over and over again - the browser just keeps eating up my memory. The problem arises from (maybe the incorrect ...
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27 views

Swap used even though most memory is “cached”? [duplicate]

I'm trying to make sense of this free -m output: total used free shared buffers cached Mem: 7971 7608 363 1 17 4703 ...
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2answers
98 views

How much RAM should an SSH connection typically use?

I'd like to ask about how much memory an SSH connection should take typically. Here is how I'm finding out how much of a RAM hit is incurred: Kindly don't get vehement that I'm using a GoDaddy shared ...
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1answer
36 views

Redhat: Swap Memory Used is Much Higher Than Total

The top command showed the following information: Mem: 132110132k total, 10447536k used, 121662596k free, 76120k buffers Swap: 16777212k total, 18446744063504593392k used, 10221735436k free, ...
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Why does /proc/*/status not account for all swap used on a system?

I have a system that has been swapping recently and am unable to account for all swap that is shown as in use by tools like 'free' or 'top'. Specifically, I can account for 19GB of 28GB swap used ...
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51 views

determine the actual memory usage of several processes that share a large memory segment

I just took a look at the output of top and it showed me (amongst other processes) the following: As once can see I have ten processes consuming approx 10GB each so 100GB in total. The computer ...
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PDOException: SQLSTATE[HY000]: General error: 23 Out of resources when opening file xxxx.MYD' (Errcode: 24) [duplicate]

I am getting this error message when trying to access a php page: PDOException: SQLSTATE[HY000]: General error: 23 Out of resources when opening file xxxx.MYD' (Errcode: 24) How can I solve this ...