Changes/SwapOnZRAM

swap on ZRAM

Summary

Swap is good, unless it's slow. ZRAM is a compressed RAM disk, a kernel feature that presents a /dev/zramX block device that can be formatted as a swap device. The ZRAM block device can be assigned a size, but the actual RAM consumption is dynamically allocated and deallocated on demand.

This change will result in the inclusion of an upstream systemd rust-zram-generator on Fedora (all editions and spins). The presence of the generator will not enable swap-on-zram. Enabling swap-on-ZRAM will further require presence of a properly formatted configuration file.

This change proposal recommends all Fedora editions and spins opt into the feature. But at the time of this proposal the opt in candidates are:

- Fedora Workstation edition - All Fedora install ISOs

Fedora installation ISOs have been using an Anaconda provided systemd service unit and script, to setup swap-on-ZRAM, for several years. Likewise, Fedora IoT uses swap-on-ZRAM since inception, using its own systemd unit and script (functionally similar to Anaconda but in its own package). This proposal recommends converging on a single implementation.

The kernel supports multiple (up to 32) swap devices. The

Owner

• Name: Chris Murphy
• Email: chris@fedoraproject.org

Current status

• Targeted release: [[Releases/<number> | Fedora <number> ]]
• Last updated: 2020-05-29
• 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>

Scope

• Proposal owners:

• Other developers: N/A (not a System Wide Change)

• Release engineering: #Releng issue number (a check of an impact with Release Engineering is needed)

• Policies and guidelines: N/A (not a System Wide Change)

• Trademark approval: N/A (not needed for this Change)

Upgrade/compatibility impact

N/A (not a System Wide Change)

How To Test

N/A (not a System Wide Change)

Dependencies

N/A (not a System Wide Change)

Contingency Plan

• Contingency mechanism: (What to do? Who will do it?) N/A (not a System Wide Change)
• Contingency deadline: N/A (not a System Wide Change)
• Blocks release? N/A (not a System Wide Change), Yes/No
• Blocks product? product

Documentation

N/A (not a System Wide Change)