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I want to pre-load some Files / Programs into the memory, ram, cache to open / access them faster.

I already tried creating a tmpfs, ramfs System https://wiki.ubuntuusers.de/RAM-Disk_erstellen (Sorry its in German) by calling those commands for Example

sudo mount -t ramfs ramfs /media/ramdisk 
sudo mount -t tmpfs -o size=20% none /media/ramdisk

and put some data (arround 1GiB) in it.

I also tried pre-loading the Files directly Mount /usr in RAM (loading from HDD when starting, and saving to when shutting down) (top answer)

cat /bin/* /lib/* /usr/bin/* /usr/lib/* >/dev/null

or

ionice -c 3 find /bin /usr/bin /usr/lib* -type f -exec ionice -c 3 cat '{}' ';' > /dev/null &

but regardless what I’m doing I see no Ram Change via System Monitor / htop

Its always around 1,7GiB / 3,8GiB I’m running Lubuntu 14.10

Do you know of any limitations for doing so running a Ubuntu System or is there something else to do to archive what I want or am I missing some other important Point?

hypnomaki
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    Run free -h for detailed data about RAM usage. Notice the "cached" collumn – leorize Jul 22 '15 at 10:17
  • Here's the Output: 3,8G [total] 3,6G [used] 1,5G [cached]

    But why is "free" showing other values than htop?

     – hypnomaki Jul 22 '15 at 10:51
  • Just googled it by my self http://askubuntu.com/questions/369466/memory-usage-statistics-different-in-free-and-htop So i think you solved my question ^^ The only thing left to do for me is to measure the speed improvement now – hypnomaki Jul 22 '15 at 10:54
  • and also this is a good reference for this question.... so it is really all about how memory is actually counted... I totally missed that http://unix.stackexchange.com/questions/176309/tmpfs-creating-file-in-tmpfs-does-not-change-memory-usage-in-htop-top – hypnomaki Jul 22 '15 at 10:56
  • Glad you solved it yourself. I recommend using preload instead of manually load every libs and binary to RAM. Preload can profile your usage and select binaries and libraries that you often use and load them to RAM automatically – leorize Jul 22 '15 at 11:50
  • I've been running preload for a month but could'nt measured big differences..... also thought about using prelink since its more configurable but never tested it so far. do you know about prelink? – hypnomaki Jul 22 '15 at 12:06
  • You could read about it from the Arch Wiki. HDD and CPU nowadays are fast enough so that differences are negliable. I suggest reading Maximizing Performance if you want to increase your PC performance – leorize Jul 22 '15 at 15:44

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