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* Tracker bug: <will be assigned by the Wrangler>
* Tracker bug: <will be assigned by the Wrangler>
* Release notes tracker: <will be assigned by the Wrangler>
* Release notes tracker: <will be assigned by the Wrangler>


== Detailed Description ==
== Detailed Description ==
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The "var" subvolume will be located at the top-level of the Btrfs file system, along-side the "root" and "home" subvolumes. An entry in `/etc/fstab` will mount it at `/var` during startup.
The "var" subvolume will be located at the top-level of the Btrfs file system, along-side the "root" and "home" subvolumes. An entry in `/etc/fstab` will mount it at `/var` during startup.


== Feedback ==
== Feedback ==
<!-- Summarize the feedback from the community and address why you chose not to accept proposed alternatives. This section is optional for all change proposals but is strongly suggested. Incorporating feedback here as it is raised gives FESCo a clearer view of your proposal and leaves a good record for the future. If you get no feedback, that is useful to note in this section as well. For innovative or possibly controversial ideas, consider collecting feedback before you file the change proposal. -->
<!-- Summarize the feedback from the community and address why you chose not to accept proposed alternatives. This section is optional for all change proposals but is strongly suggested. Incorporating feedback here as it is raised gives FESCo a clearer view of your proposal and leaves a good record for the future. If you get no feedback, that is useful to note in this section as well. For innovative or possibly controversial ideas, consider collecting feedback before you file the change proposal. -->


== Benefit to Fedora ==
== Benefit to Fedora ==
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** changes to lorax and anaconda as needed so that Silverblue and Kinoite variants have their own installation kickstart, such that automatic/guided installation automatically creates "var".
** changes to lorax and anaconda as needed so that Silverblue and Kinoite variants have their own installation kickstart, such that automatic/guided installation automatically creates "var".
*** possible liability, determine whether the the addition of /var mount point for Btrfs scheme results in /var mount point for other schemes (and inhibit)
*** possible liability, determine whether the the addition of /var mount point for Btrfs scheme results in /var mount point for other schemes (and inhibit)


== Upgrade/compatibility impact ==
== Upgrade/compatibility impact ==
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== How To Test ==
== How To Test ==
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working like it's supposed to?
3. What are the expected results of those actions?
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* Do a clean installation and check `df` and `/etc/fstab` for an explicitly listed `/var` mount point.
* Do a clean installation and check `df` and `/etc/fstab` for an explicitly listed `/var` mount point.
<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->




== User Experience ==
== User Experience ==
<!-- If this change proposal is noticeable by users, how will their experiences change as a result?
This section partially overlaps with the Benefit to Fedora section above. This section should be primarily about the User Experience, written in a way that does not assume deep technical knowledge. More detailed technical description should be left for the Benefit to Fedora section.
Describe what Users will see or notice, for example:
  - Packages are compressed more efficiently, making downloads and upgrades faster by 10%.
  - Kerberos tickets can be renewed automatically. Users will now have to authenticate less and become more productive. Credential management improvements mean a user can start their work day with a single sign on and not have to pause for reauthentication during their entire day.
- Libreoffice is one of the most commonly installed applications on Fedora and it is now available by default to help users "hit the ground running".
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* The change won't generally be noticeable to users
* The change won't generally be noticeable to users
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== Dependencies ==
== Dependencies ==
<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this change depends?  In other words, completion of another change owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel change)? -->
<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->


* Anaconda/blivet, lorax, and possibly kickstarts
* Anaconda/blivet, lorax, and possibly kickstarts
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== Contingency Plan ==
== Contingency Plan ==


<!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration".  Or it might not (e.g. rebuilding a number of dependent packages).  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
* Contingency mechanism: (What to do?  Who will do it?) N/A (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
* Contingency deadline: beta freeze (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Contingency deadline: beta freeze (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
<!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
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== Documentation ==
== Documentation ==
<!-- Is there upstream documentation on this change, or notes you have written yourself?  Link to that material here so other interested developers can get involved. -->


No significant documentation is planned other than this change proposal.
No significant documentation is planned other than this change proposal.

Revision as of 03:29, 18 January 2022

Silverblue and Kinoite will have /var on its own Btrfs subvolume

Summary

Silverblue and Kinoite: For new clean automatic (guided) installations, create a "var" subvolume to be mounted at /var.


Owner


Current status

  • Targeted release: Fedora Linux 36
  • Last updated: 2022-01-18
  • FESCo issue: <will be assigned by the Wrangler>
  • Tracker bug: <will be assigned by the Wrangler>
  • Release notes tracker: <will be assigned by the Wrangler>


Detailed Description

Currently, Silverblue and Kinoite mimic other Fedora desktops. There is a "root" subvolume mounted at / and a "home" subvolume mounted at /home.

This proposal adds a "var" subvolume to be mounted at /var.

The "var" subvolume will be located at the top-level of the Btrfs file system, along-side the "root" and "home" subvolumes. An entry in /etc/fstab will mount it at /var during startup.


Feedback

Benefit to Fedora

Users who opt into Btrfs features like snapshots and rollbacks.

  • By moving /var into its own subvolume, it will be excluded from snapshots and rollbacks of the "root" subvolume, which contains /etc and /usr.
  • Users will find it straightforward to rollback "root" while not rolling back "var": including logs, VMs, databases, and so on.
  • The ability to snapshot only "var" and use Btrfs send/receive to replicate only "var" permits for an efficient way of backing up the variable system data.
    • A clean install can restore the "root", therefore it doesn't strictly need to be backed up. Meanwhile "var" and "home" can be restored using snapshot replication via send/receive.


Scope

  • Proposal owners:
    • changes to lorax and anaconda as needed so that Silverblue and Kinoite variants have their own installation kickstart, such that automatic/guided installation automatically creates "var".
      • possible liability, determine whether the the addition of /var mount point for Btrfs scheme results in /var mount point for other schemes (and inhibit)


Upgrade/compatibility impact

Change will not be applied to upgrades. But we can document steps to apply the change to existing installations.


How To Test

  • Do a clean installation and check df and /etc/fstab for an explicitly listed /var mount point.


User Experience

  • The change won't generally be noticeable to users
  • Users will see an additional /var mount point in /etc/fstab, and df
  • Some utilities, notably backup programs like borg backup, and rsync with -x option, will treat Btrfs subvolumes as separate file systems and may not descend (recursively) into them.


Dependencies

  • Anaconda/blivet, lorax, and possibly kickstarts


Contingency Plan

  • Contingency deadline: beta freeze (not a System Wide Change)
  • Blocks release? No


Documentation

No significant documentation is planned other than this change proposal.

N/A (not a System Wide Change)

Release Notes

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