More robust iso

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Make SoaS .isos more robust by removing the compressed CoW indirection layer for root fs / sole partition.


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Current status

  • Targeted release: SoaS v4
  • Last updated: Mchua 18:36, 11 June 2010 (EDT)
  • Percentage of completion: 0%

Detailed Description

SoaS sticks regularly fail in an irrecoverable manner after a certain volume of writes to the image; when the overlay runs out of storage, it corrupts the entire overlay the compressed ext3 filesystem fails when the overlay runs out of storage.

normal fs = "sorry, can't write your file that you just tried to write cause the disk is full"

overlay fs = "sorry, can't write your file and I just corrupted everything you ever wrote to the overlay".

Our current thinking is that this goal is achievable with a bit of scripting that takes the livecd-tools .iso image we get now and...

  1. creates a pre-partitioned disk image (cue loads of partition / cylinder /etc. nuances here)
  2. unrolls the livecd-tools' nested filesystems and copies the contents to the disk image from #1
  3. does any hacking of the filesystem contents necessary to remove any undesirable assumptions about the livecd-tools' filesystem configuration.

Benefit to SoaS

SoaS stick failure is inevitable after a certain volume of writes right now because the overlay will run out of the finite amount of space it has. This eliminates this method of stick failure.

#1798 is the relevant ticket.


What work do the developers have to accomplish to complete the feature in time for release? Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?

UI Design

Does the feature have a direct impact on the work flow, or does it need a UI? Link here mockups, or add detailed descriptions.

How To Test

More robust iso/Testing

User Experience

If this feature is noticeable by its target audience, how will their experiences change as a result? Describe what they will see or notice.


What other packages (RPMs) depend on this package? Are there changes outside the developers' control on which completion of this feature depends? In other words, does your feature depend on completion of another feature owned by someone else or that you would need to coordinate, which might cause you to be unable to finish on time? Other upstream projects like Python?

Contingency Plan

If you cannot complete your feature by the final development freeze, what is the backup plan? This might be as simple as "None necessary, revert to previous release behaviour." Or it might not. If your feature is not completed in time, we want to assure others that other parts of Sugar will not be in jeopardy.


Is there upstream documentation on this feature, or notes you have written yourself? Has this topic been discussed in the mailing list or during a meeting? Link to that material here so other interested developers can get involved.

The below links are not sorted, but are here for reference when this feature proposal is being written up in more detail. Not all of them may be useful, as a warning for the next person to tackle this page. Mchua 19:04, 11 June 2010 (EDT)

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