SD card unpartitioned space -- used for swap?

Martin Langhoff martin.langhoff at
Mon Nov 22 11:03:26 EST 2010

from the department of opportunity-bearing-tradeoffs...

For XO-1.5 we build our OS images to be a bit "short" of the stated SD
card size, because different SD cards placed in mfg vary in exact

That means we always have a bit of space left over. We could add an
init script that sets up a small swap partition right there.

Technically it's not a big deal, it's reasonably fast (for
first-boot). Needs to be combined with a low-swappiness sysctl setting
(so as to avoid pointless SD Card wearout).

The upside is that we'd have the Linux kernel able to use its VM as it
wishes. We're pretty alone in trying to run a general purpose desktop
distro without VM, and we sure pay the price for that currently.


 - XO-1 gets left alone in VM-lessness.

 - Increased SD card wear (should it matter? Our qualification process
is stringent... so if it passed, we should get to use the damn

 - Slightly longer first boot

 - Slightly more fragile first boot (can we make it failsafe?)

 - ???


 martin.langhoff at
 martin at -- School Server Architect
 - ask interesting questions
 - don't get distracted with shiny stuff  - working code first

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