i try to find where my memory:

i use program mema.py which sum memory usage by processes (ps aux --sort -rss) according program 22% (3713500 kb) memory used by programs (i get 16Gb RAM )

free reports:

             total       used       free     shared    buffers     cached
Mem:      16431416   14773344    1658072     440524     234416    1780688
-/+ buffers/cache:   12758240    3673176
Swap:     43528916          0   43528916

(14773344 kb used total) - (1780688 cached) - (234416 cached buffers) - (3713500 app) = 9044740

so where 9Gb ? For what and what they are used for?

debian 8.8 Linux acrhlx 3.16.0-4-amd64 #1 SMP Debian 3.16.43-2 (2017-04-30) x86_64 GNU/Linux

Update i found my memory it consumed by ZFS it not reported in buffers+cached, not sure bug it or feature more about zfs


2 Answers 2


Used does not mean what you think it means; used includes memory that is in use but can be made available (i.e. is not currently used by applications). For details read this.

Further, I do not believe that ps aux --sort -rss will show everything. I cannot see the kernel in there for instance (see cat /proc/meminfo|grep Slab) ... or the kernel modules (see the second column of cat /proc/modules). For details see this answer on Unix & Linux Stackexchange which incidentally is where this question actually belongs in my opinion.

  • i know about Used column, kernel slab accounted in Buffers + Cached columns, i take it in account, i too not believe in ps aux, but what to use to get information about 9Gb of RAM, for what and what they are used for?
    – acr
    Commented May 13, 2017 at 9:08

ZFS module not reported in buffers+cached

i update my memory analyser tool that help to find problems like that


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