[OLPC-AU] Golden image restores for laptops in shared use scenarios

James Cameron quozl at laptop.org
Tue Jan 18 00:05:11 EST 2011


Occasionally a laptop operating system needs to be reinstalled for
testing, or where the laptop is transferred to another owner, or where
the laptop is shared as a teaching resource.

Reinstalling in the supported fashion costs roughly 20 minutes on an
XO-1.5, due to the complete block by block rewrite of the internal SD
card.

Reinstalling a batch of laptops costs 20 minutes for the first one, then
roughly 50 minutes for the rest, using NANDblaster.

An alternative to a complete rewrite is a filesystem synchronisation,
from a master filesystem to the target laptop.  Only the changes
necessary are sent over the wireless.  This costs about four minutes per
laptop using the tools I've just written.

Usage scenario:

1.  boot a master laptop that contains a pristine filesystem (or place
a copy of the filesystem on a server),

2.  for each target laptop, boot using a USB drive, remove the drive,
and start a script "xo-server".

More detail and tested procedure at:
http://wiki.laptop.org/go/Tiny_Core_Linux/Reversion

Risks:

- filesystem corruption of the master laptop would be copied to the
  other laptops,

- accidental boot of the master laptop may cause side-effects such as
  loss of collaboration in Sugar,

- minor differences in filesystem allocation may occur, but since the
  internal storage is non-rotating there should be no significant change
  to activity response times.

- not supported by OLPCA's deployment support team.

-- 
James Cameron
http://quozl.linux.org.au/


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