FullFilesystemSanityGutsy
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Launchpad Entry: foo
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Summary
The system should handle disk full situations gracefully.
Use Cases
- Michael is an Ubuntu user, and downloads huge numbers of files and fills his disk. This should only prevent him saving further files to the disk, and may cause some applications that he starts to fail. It should not stop the general desktop from operating normally.
- If Michael reboots, the computer should boot up normally and allow him to login. It should warn him that he has no free disk space. The general desktop should still operate normally; however applications may prevent him from saving files, or may not function. If he uses the file manager to free up disk space, he should be able to immediately resume using his computer normally; saving files from applications, and using those that cannot operate without writing to disk, and he should not need to reboot or log in again or restart any application.
Rationale
Current disk full behaviour in Ubuntu is very poor. BootLoginWithFullFilesystem (also targeted for gutsy) will fix the worst problems and at least allow the user to recover, but we would like the system not to misbehave and not to
Approach and Scope
This is an ambituous goal. Without a fully automatic functional test of every component in the system, complete success will be unattainable and future regressions will be difficult to detect. However, we expect to be able to find and fix the most important cases and expect them to regress only slowly:
We will concentrate on core software (defined here as software which is installed by default and which runs between power-on and the user's desktop readiness including the file manager). We hope that filesystem full misbehaviour we discover and fix will be regarded as bugs by upstream and regress relatively rarely.
(Here "misbehaviour" and "bug" refer to violations of the intent of the Use Case, specified above.)
We propose to create a test environment which will allow us to monitor the software under test during startup and use. This will identify the specific programs and subsystems which attempted to write to disk but failed to do so; we will then apply ad-hoc techniques (including debugging, ad-hoc testing and source code inspection) to ensure that each such identified case does not constitute or trigger a bug.
Other applications
As time permits, the same tests can be performed on specific other applications of interest. OpenOffice.org is an obvious candidate.
Firefox (and other programs in the Mozilla suite) are not expected to be tractable: the Mozilla profile management system is known to regularly write to disk and not to handle out of disk space conditions well. The profile management system itself is unsuitable for handling disk full in a coherent way, and upstream do not seem to have the resources or priorities which would allow these problems to stay fixed for any length of time.
Release Note
This section should include a paragraph describing the end-user impact of this change. It is meant to be included in the release notes of the first release in which it is implemented. (Not all of these will actually be included in the release notes, at the release manager's discretion; but writing them is a useful exercise.)
It is mandatory.
Assumptions
If we find and fix a disk full bug in the software we really care about, it is unlikely to regress so quickly that the manual work done pursuant to this spec quickly becomes irrelevant.
Design
You can have subsections that better describe specific parts of the issue.
Implementation
This section should describe a plan of action (the "how") to implement the changes discussed. Could include subsections like:
UI Changes
Should cover changes required to the UI, or specific UI that is required to implement this
Code Changes
Code changes should include an overview of what needs to change, and in some cases even the specific details.
Migration
Include:
- data migration, if any
- redirects from old URLs to new ones, if any
- how users will be pointed to the new way of doing things, if necessary.
Test/Demo Plan
It's important that we are able to test new features, and demonstrate them to users. Use this section to describe a short plan that anybody can follow that demonstrates the feature is working. This can then be used during CD testing, and to show off after release.
This need not be added or completed until the specification is nearing beta.
Outstanding Issues
This should highlight any issues that should be addressed in further specifications, and not problems with the specification itself; since any specification with problems cannot be approved.
BoF agenda and discussion
Use this section to take notes during the BoF; if you keep it in the approved spec, use it for summarising what was discussed and note any options that were rejected.