![]() ![]() A swap partition is faster, but it is easier to change the size of a swap file (there's no need to repartition the whole hard disk, and possibly install everything from scratch). Linux can use either a normal file in the filesystem or a separate partition for swap space. The part of the hard disk that is used as virtual memory is called the swap space. Of course, reading and writing the hard disk is slower (on the order of a thousand times slower) than using real memory, so the programs don't run as fast. This is all made completely transparent to the user programs running under Linux only see the larger amount of memory available and don't notice that parts of them reside on the disk from time to time. When the original contents are needed again, they are read back into memory. The kernel will write the contents of a currently unused block of memory to the hard disk so that the memory can be used for another purpose. Linux supports virtual memory, that is, using a disk as an extension of RAM so that the effective size of usable memory grows correspondingly. Will be counted in VIRT and SHR, but only the parts of the libraryįile containing the functions being used will actually be loaded in Uses a few functions in a library, the whole library is mapped and In the case of libraries, it does not necessarily mean SHR indicates how much of the VIRT size is actually sharable (memory (This alsoĬorresponds directly to the %MEM column.) This will virtually alwaysīe less than the VIRT size, since most programs depend on the C Of how much actual physical memory a process is consuming. RES stands for the resident size, which is an accurate representation Program is able to access at the present moment. Have been mapped into it (most notably shared libraries), and memory ![]() Instance the video card’s RAM for the X server), files on disk that Memory it is actually using, memory it has mapped into itself (for VIRT stands for the virtual size of a process, which is the sum of If you have any questions or suggestions, let me know in the comments.I found this explanation from Mugurel Sumanariu very clear: You also learned to check memory usage in real-time. That was good, right? Now you know how to check RAM size in Ubuntu command line. What you need to focus here is the total size (you already know), speed and type of RAM.Īs you can see in the screenshot above, I have LDDR4 RAM with 4276 MT/s of speed. Memory Subsystem Controller Product ID: Unknown Memory Subsystem Controller Manufacturer ID: Unknown Memory Operating Mode Capability: Volatile memory My system in the example has 8 cores and it repeats the same for 8 times. You'll see part of the output is repeated for each core of processors you have. Yes, you need to use sudo or be root to use this command. To see the RAM details, you should filter its output on the memory like this: sudo dmidecode -type memory The dependable DMI table decoder command dmidecode gives you all kinds of information about your system's hardware. Let's see how can you see what type of RAM your system has. That's enough discussion on the memory unit. To exit the top command, press the Ctrl+C keys. ![]() ![]() You can press Shift+M to sort it by memory. Just run the command in the terminal: topīy default, the top command output is sorted by CPU consumption. Not only does it show the total memory usage in real-time, but it also shows the memory consumption by various processes. To stop the continuously running command, press Ctrl+C.Īn alternative and in my opinion better way is to the top command. This will change the output of the free command after every 2 seconds. If you want to keep a tab on the memory usage, you can combine the watch and free command. If your system is often running out of available RAM, you should consider adding swap space to your Ubuntu machine. This available RAM is the free RAM your system can use. You have to focus on the Mem row and the total and available columns.Īs you can see, my Ubuntu server (running this site) has 1.9 GB of total RAM and 1.1 GB of available RAM. Total used free shared buff/cache available You should see an output like this: free -h This means that you get to see the RAM size in GB, MB etc instead of in bytes. The -h option displays the output in a human-readable format. You can use the free command to display the amount of free and used memory (RAM) in the system. In this tutorial, I'll show you how you can achieve the following in the terminal:Ĭheck the total RAM size and the free RAM You may even want to check the kind of RAM it is (DDR1 or DDR2). As someone who manages Ubuntu servers, you'll need to know how much RAM your system has, and how much of the RAM is free to use. ![]()
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