What a Memoiry Commited and Memory Commited is 103%

General
1

Hello,
I’m Trainee and Student system and network computer (IT).
I want understand a Memory Commited (RAM + SWAP ?) and why memory commited is 103% on server Debian ?
I

Best Regard,
Hassan

2

Hi @mrhassan60,

you hit the forum for the checkmk product and your question is not specific for monitoring but a general question about memory management on UNIX/Linux systems.
You can find out more about memory on Linux with included manual pages (command man) on your system or just googling around the topic linux memory management.

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Ok, i write on checkmk forum because a warning alert on a checkmk monitoring for server debian.

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and why memoriy commited use is 103% (18Gb of of 16Gb) on server linux

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That’s because the server is configured to over commit memory and reports it’s values to checkmk. The default monitoring thresholds for memory on linux servers is to warn if the memory committed exceeds the installed RAM. This is important in the case you like to uninstall the swap and all pages need to be written back to the RAM, which is in this case not possible anymore.

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There is a good introduction article to Linux memory monitoring with Checkmk: Top Insights You Need to Know About Linux Swap Monitoring | Checkmk

A Linux system can (and does, by default) overcommit memory. This means that processes can acquire more memory than they actually need. Linux commits these requests, but does not reserve a physical memory segment unless the memory is really used (e.g. a write request to that memory is made). It is quite a common pattern in Linux/UNIX software to acquire memory which is never used.

The Checkmk message means that on the monitored system, there is 3% more committed memory than the RAM and SWAP together can provide. This means that if all processes start to really use the aquired memory, the system would need to kill some processes in order to fulfill the needs of the others. That is why Checkmk warns about the situation. You can avoid these situations by increasing the swap space.

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Ok, Thank for answer.

Best Regard,
Hassan

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