[sf-lug] how to run software automatically at start up; how to make a ram disk

jim jim at systemateka.com
Mon Aug 6 15:24:01 PDT 2012

Thanks lots, Ken. 
    I had to ponder some. I went to 
to read about the difference between ramfs and tmpfs 
(another to-the-point, clear, useful article). 

    Great tip about making symlinks to spare the SSD! 

    For those interested: 
* ramfs creates a ram disk and will grow as one adds 
files. Warning: ramfs will grow to consume all ram. 
* tmpfs creates a ram disk of a certain size, and as 
files grow over the ram disk size, tmpfs uses swap. 

    I believe the following mount commands do what Ken's 
/etc/fstab entries do, though they'll be gone after 
# mount -t tmpfs -o size=256M tmpfs /tmp/      ; chmod -777 /tmp/ 
# mount -t ramfs -o size=250M ramfs /var/log/  ; chmod 755 /var/log/ 

    and an example symlinks command might be 
# ln -s /tmp/ /var/cache/apt/archives/ 

On Mon, 2012-08-06 at 14:53 -0700, Ken Shaffer wrote:
> Hi Jim,
> For my usb setup, I just put in the below two line into fstab:
> # update-manager cannot see any space in /tmp when ramfs used
> tmpfs        /tmp        tmpfs    size=256M,mode=1777    0    0
> ramfs        /var/log    ramfs    mode=755        0    0
> Then any program using /tmp gets the benefit of fast ram-based access.
> I can then add specific links to /tmp, like /var/cache/apt/archives,
> so my package
> downloads for updates don't need to write to the usb flash memory.
> Ken

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