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63
votes
3answers
56k views

Meaning of the buffers/cache line in the output of free

Why does my server show total used free shared buffers cached Mem: 12286456 11715372 571084 0 81912 6545228 -/+ buffers/cache: 5088232 7198224 ...
28
votes
3answers
3k views

Why is Linux reporting “free” memory strangely?

This is a canonical question about how Unix operating systems report memory usage. Similar Questions: Server refuses to use swap partition Memory Usage in LINUX I have production ...
16
votes
2answers
4k views

Where did my RAM go?

Note: before you jump in too fast, yes I read linuxatemyram.com! I have a server with 64GB RAM. free -m says that my RAM is full, and it's not because of disk caching: total used ...
13
votes
2answers
11k views

Effects of configuring vm.overcommit_memory

My VPS web server running on CentOS 5.4 (Linux kernel 2.6.16.33-xenU) irregularly (like once a month give or take a few weeks) becomes unresponsive due to oom-killer kicking in. Monitoring of the ...
13
votes
6answers
39k views

Weird memory usage in Windows Server 2008 R2

I hope someone can help. We've got a Windows Server 2008 R2 machine with 16GB of RAM that keeps getting all its available memory eaten by something. Nothing in Task Manager or Resource Monitor reveals ...
12
votes
11answers
15k views

A monitoring tool that captures processes' memory usage/cpu usage, etc over time

I am looking for a way to diagnose issues, such as swap death, where a balooning memory process fills up swap and kills the whole machine (such as apache). I'm already using cacti and I can set up ...
10
votes
1answer
3k views

How large is my ZFS dedupe table at the moment?

I have read a lot of information about planning RAM requirements forZFS deduplication. I've just upgraded my file server's RAM to support some very limited dedupe on ZFS zvols which I cannot use ...
9
votes
3answers
21k views

Something eats all memory (I suspect memory leak on some app). How to detect what?

I have server which runs liquidsoap+icecast bundle and simple website (httpd+mysqld). Nothing special. Visitors around 2000+ per day, with around 50 being online simultaneously on average. Server has ...
9
votes
5answers
11k views

check history of cpu/memory usage in ubuntu?

Is there a way for me to review cpu or memory usage on my ubuntu linux server? I've noticed my server (lamp set up) being slow at times, but by the time I log in as root and run a PS command, ...
8
votes
2answers
17k views

Used memory on Solaris 10

One more question about memory on Solaris 10. A top shows me that I have 672 MB free memory : 130 processes: 126 sleeping, 2 zombie, 2 on cpu CPU states: 95.1% idle, 3.9% user, 1.0% kernel, 0.0% ...
8
votes
2answers
4k views

Is it possible to list the files that are cached?

Here the output of free -m: total used free shared buffers cached Mem: 7188 6894 294 0 249 5945 -/+ buffers/cache: ...
8
votes
1answer
1k views

PHP on command line displays “Out of Memory”, no file name, line number or memory value

I originally posted this at http://stackoverflow.com/questions/9665189/php-on-command-line-displays-out-of-memory but was advised to post here instead. This is not the normal fatal error when you run ...
7
votes
7answers
21k views

How much RAM does a server actually need?

I have a quite a few servers deployed around the world. They are running Windows 2003 x64 with SQL Server 2005 x64 with 6 GB of RAM. The boxes do not have the best (or even an acceptable) ...
7
votes
1answer
5k views

Apache memory usage optimization

Apache is using too much of my server memory causing it to crash. I have 4GB of RAM in the server. I'm trying to fine tune Apache settings in order to improve it's performance but I'm quite new at ...
6
votes
5answers
3k views

Free / Cached / Available memory on Linux

I have read that linux uses free memory for caching, to make system faster. However, both Nagios and Paessler PRTG monitoring system show me that my memory usage is critical. I could change Nagios ...
6
votes
2answers
2k views

apache eats up too much ram per child

I've got fallowing problem: Apache eat to many ram per child. The fallowing comments shows: cat /etc/redhat-release -- Fedora release 8 (Werewolf) free -m: total used ...
6
votes
1answer
5k views

Linux not freeing large disk cache when memory demand goes up

Running Ubuntu on a 2.6.31-302 x86-64 kernel. The overall problem is that I have memory in the 'cached' category that keeps on going up and will not be freed or used even when our application needs ...
5
votes
5answers
14k views

How can I monitor memory usage for a windows-based JVM and trigger an alert if it gets too high?

I have an app that runs as a JVM in Windows 2008. I'd like to monitor it's memory usage and be sent an email if/when memory usage reaches a specific threshold. Is there a free utility or method for ...
5
votes
2answers
5k views

Apache “httpd” process, utilizing all my servers memory

My small ec2 instance with 1.7 GB memory, running the Amazon AMI based off of CentOS, has an issue with Apache utilizing way too much memory than it should. If you take a look at the screenshot, the ...
5
votes
1answer
8k views

Meaning of Cached Available and Free Memory in Task Manager's Performance “Physical Memory” section?

I want to see how much of the RAM is being used by my system. When I go to Task Manager -> Performance and look under "Physical Memory (MB)" section, it lists 4 terms which are:- Total Cached ...
5
votes
2answers
395 views

Automatically suspend/hibernate a process when too much memory taken

I'm running a small Debian compute cluster on 8-core PCs with 16GB of RAM. I'm running batches of about 1k tasks (each batch has a total expected time of a month to be finished). A single task is ...
5
votes
2answers
1k views

How quickly will SQL Server release RAM when the OS signals a low memory condition?

From the SQL Server 2008 R2 Books Online: Server Memory Options When SQL Server is using memory dynamically, it queries the system periodically to determine the amount of free physical ...
4
votes
1answer
2k views

Memory Usage on Linux box does not match up with `free`

I have a Linux machine that is not running too much in the way of software, but is somehow using 1.7GB of the 2GB of the installed memory. When I run free, I get: total used ...
4
votes
3answers
4k views

Why does 'top' indicate low memory usage, whilst 'free' indicates high memory usage?

Why does 'top' indicate low memory usage, whilst 'free' indicates high memory usage? Mem: 262144k total, 225708k used, 36436k free, 47948k buffers Swap: 262136k total, 40k used, ...
4
votes
3answers
729 views

How to check if ESX hosts have enough RAM

I have noticed that some Linux based virtual machines become gradually slower until I reboot them. At first I suspected hacking and resource abusing but after several vm rebuilds from the scratch and ...
4
votes
2answers
1k views

Windows 2008 R2 Server using 100% RAM, can't find the problematic process

OK so I have a W2008 R2 server running a single website with about 100-200 visitors daily, and it also has MSSQL 2008 running on it for the same website. Recently, when the server starts it uses a ...
4
votes
2answers
436 views

Simultaneously high swap and unused memory on Ubuntu server

I have an Ubuntu 10.04 web server in the cloud, with 1 GB of RAM. Here's a memory chart from Munin: but I'm having trouble making sense of it: on the one hand, unused memory is very high; but swap ...
4
votes
3answers
151 views

Where can I find the source for the unix app 'free'?

Free is a rather hard word to Google for, all my variations failed to bring up anything related to the unix app free (it's for viewing memory usage - free -m etc.). If anyone has a link to the source ...
4
votes
1answer
12k views

determining free memory from command line on Windows

I would like to monitor the free memory on four machines each running Windows Server 2003 R2 SP2 64-bit. Each box has 31.7gb of RAM. I would like to periodically run a command line tool so I can ...
4
votes
2answers
3k views

How do I view NTFS metadata?

On a Windows Server 2008 R2 file server, we are encountering a memory usage problem. We used RAMMap to troubleshoot, and found that 10GB of NTFS Metadata is being cached in memory and never gets ...
4
votes
2answers
172 views

Mystery process crashing machine by using all of the RAM - how to identify?

I have a Linux machine which runs ~10 in house written processes. Every other day(!) the machine completely runs out of RAM, goes into swap and becomes unresponsive. This happens quickly over a ...
4
votes
2answers
915 views

VMware ESX virtual machine, Windows 2008 Server R2, memory full but process total nowhere near?

We have set up a TFS 2010 server on a Windows 2008 R2 server, and it has recently started to time out and give long operation timings. When I log on to the machine I can see that task manager ...
4
votes
2answers
8k views

Apache heavy load VIRT vs RES memory

I have a Debian 5 server, which gets a lot of traffic. Right now the server has 4 GB of RAM and no swap memory. I see in top that Apache processes consume roughly 180 MB virtual memory (VIRT) each, ...
4
votes
2answers
210 views

Server overloaded, acts like out of memory, but thats not true

I have a Centos 6.5 server, running QEMU-KVM virtualization: hardware: 40 CPUs 400 GB RAM software: Kernel: 2.6.32-431.17.1.el6.x86_64 Qemu: 0.12.1.2 Libvirt: 0.10.2 There are 3 guests, with ...
4
votes
1answer
1k views

Very high memory usage, but not claimed by any process?

While stress-testing LVM on one of our Debian servers, I came across this issue where memory would fill up a lot to the point where it would run the server out of memory, but no process would claim ...
4
votes
1answer
761 views

Very high RAM buffers usage following instance resize/reboot

Yesterday afternoon, we resized one of our Linode instances (CentOS 5.7, 64-bit) from a 4GB instance to 12GB. Immediately following that reboot, I noticed that memory usage for buffers was insanely ...
4
votes
1answer
1k views

How can I get memory usage reported in SNMP under Mac OS X 10.8 Server?

I have two servers running Mac OS X 10.8.3 Server (Build 12D78) with SNMP reporting enabled. I have a cacti server set up collecting data from these hosts. My Load Average, CPU Usage, Disk Space Usage ...
4
votes
3answers
3k views

Windows Server task manager displays much higher memory use than sum of all processes' working set size

I have a 16 GB Windows Server 2008 x64 machine mostly running SQL Server 2008. The free memory as seen in Task Manager is very low (128 MB at the moment), i.e. about 15.7 GB are used. So far, so good. ...
3
votes
2answers
322 views

Why is SQL Server 2005 consuming so much memory (and it is not even running)

Lately, I have noticed that SQL Server is consuming too much memory even though the Management Studio is not running. It consumes as much as 500,000K of memory. I understand that the SQL Server ...
3
votes
2answers
879 views

SQL 2008 Memory Usage

I have a SQL Server 2008 (ver 10.0.1600) running on a Windows Server 2008 R2 Enterprise server with 8 GB of physical ram. If I open Task Manager I can see on 'Physical Memory' section of 'Performance' ...
3
votes
3answers
3k views

What can cause kernel out_of_memory error?

I'm running Debian GNU/Linux 5.0 and I'm experiencing intermittent out_of_memory errors coming from the kernel. The server stops responding to all but pings, and I have to reboot the server. # uname ...
3
votes
3answers
1k views

Debian squeeze high memory usage?

I am quite new in the Linux / Server environment. I installed Debian Squeeze on vmWare Server to run LAMP. After I had the LAMP configured and running I decided to check on the memory usage of the ...
3
votes
1answer
523 views

How to measure a driver's memory consumption in Windows?

I've heard an unchecked gossip that Realtek drivers on Windows 2008 suffer from memory leakage. My computer with this network card and OS suffers exactly from this symptom - high memory consumption. ...
3
votes
1answer
768 views

How would I measure the amount of RAM needed per Glassfish domain?

In our test environment we have a lot of apps spread out over a few servers and Glassfish domains. To make versioning easier I would have liked to have one Glassfish domain per customer per app (kind ...
3
votes
1answer
2k views

Monitoring SQL Server 2008

I understand SQL Server doesn't release the memory unless the OS needs it. Then, monitoring Available Bytes (free memory) is not the best way to monitor the service. What other variables can give me a ...
3
votes
2answers
101 views

How to limit Apache sub-process memory usage?

— Yeah, just that simple question. It's too easy to consume a lot of RAM in brain-dead mod_XxX (say, mod_php) application, so I'm just wondering what does Apache allow to do as countermeasure.
3
votes
1answer
588 views

Limit private memory usage per user

I'm using cgroups with the memory controller to set a memory limit for each user (using the memory.limit_in_bytes setting). The problem is that this setting also accounts cache usage. Therefore, if ...
3
votes
1answer
2k views

How to free PHP-FPM memory?

There are several discussions complaining high memory usage of PHP-FPM, without any practical approach to overcome. As I explored the problem with numerous tests, the problem is related to the age of ...
3
votes
2answers
1k views

Ever increasing mem usage by php-fpm?

It seems php-fpm is allocating more and more memory, although peaks and dips in amount of requests. Couldn't post more than one image, so I put them here. As you can see in the uri of the pictures, ...
3
votes
1answer
574 views

Apache and memory usage

I rent a Gentoo server with the usual LAMP stack (prefork Apache MPM) + suPHP. From time to time, my server runs out of memory and slows down to a crawl (responds to pings, but it's practically ...