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I am new to running a linux server and wanted to know the difference between the total memory shown with the top command (which appears to be 78GB)

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and the free command which shows that I have 743GB of memory

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Thank you in advance!

CyberStems
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  • Welcome to the site. Please don't post screenshots of console output. They are often difficult to read, the content will not show up in search enginre results, and contributors trying to help will have to type-copy content when trying to analyze/reproduce your problem. Instead, paste it into the question using code formatting. – AdminBee Feb 04 '21 at 08:10

1 Answers1

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top's free figure is 90G. There are + signs next to the total, used and buff/cache values. top reports the same sizes as free.

See the top manual page, in particular the description of the interactive E command in section 4a:

      E  :Enforce-Summary-Memory-Scale in Summary Area
          With this command you can cycle through the available
          summary area memory scaling which ranges from KiB
          (kibibytes or 1,024 bytes) through EiB (exbibytes or
          1,152,921,504,606,846,976 bytes).

      If you see a `+' between a displayed number and the
      following label, it means that top was forced to truncate
      some portion of that number.  By raising the scaling
      factor, such truncation can be avoided.
berndbausch
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  • Thanks for your answer berndbaush, can you kindly elaborate upon what you mean by "top's free figure"? I've summed the swap, total and buff/cache memory but they do not equate to 743GB - not sure if I misunderstood how top reports the same sizes as free. Lastly I do not see the -E option for the top command.

    I greatly appreciate any further insights you can provide in helping me become a better linux user!

     – CyberStems Feb 04 '21 at 20:24
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    By "top's free figure" I mean the amount of free memory reported by top. In your screenshot, buffer cache is 452GB, used is 235GB, free is 90, total is 780GB. Finally, E is not an option but an interactive command, which you use while top is running. – berndbausch Feb 05 '21 at 00:01