https://fedoraproject.org/wiki/Changes/BtrfsTransparentCompression == Summary == On variants using btrfs as the default filesystem, enable transparent compression using zstd. Compression saves space and can significantly increase the lifespan of flash-based media by reducing write amplification. It can also increase read and write performance. == Owners == * Name: [[User:salimma|Michel Salim]], [[User:dcavalca|Davide Cavalca]], [[User:josef|Josef Bacik]] * Email: michel@xxxxxxxxxxxxxxx, dcavalca@xxxxxx, josef@xxxxxxxxxxxxxx == Detailed description == Transparent compression is a btrfs feature that allows a btrfs filesystem to apply compression on a per-file basis. Of the three supported algorithms, zstd is the one with the best compression speed and ratio. Enabling compression saves space, but it also reduces write amplification, which is important for SSDs. Depending on the workload and the hardware, compression can also result in an increase in read and write performance. See https://pagure.io/fedora-btrfs/project/issue/5 for details. This was originally scoped as an optimization for https://fedoraproject.org/wiki/Changes/BtrfsByDefault during Fedora 33. == Benefit to Fedora == Better disk space usage, reduction of write amplification, which in turn helps increase lifespan and performance on SSDs and other flash-based media. It can also increase read and write performance. == Scope == * Proposal owners: ** Update anaconda to perform the installation using <code>mount -o compress=zstd:1</code> ** Set the proper option in fstab (alternatively: set the XATTR) ** Update disk image build tools to enable compression: *** lorax *** appliance-tools *** osbuild *** imagefactory ** [optional] Add support for [https://github.com/kdave/btrfs-progs/issues/328 setting compression level when defragmenting] ** [optional] Add support for [https://github.com/kdave/btrfs-progs/issues/329 setting compression level using `btrfs property`] * Other developers: ** anaconda: review PRs as needed * Release engineering: https://pagure.io/releng/issue/9920 * Policies and guidelines: N/A * Trademark approval: N/A == Upgrade/compatibility impact == This Change only applies to newly installed systems. Existing systems on upgrade will be unaffected, but can be converted manually with <code>btrfs filesystem defrag -czstd -r</code>, updating `/etc/fstab` and remounting. == How to test == Existing systems can be converted to use compression manually with <code>btrfs filesystem defrag -czstd -r</code>, updating `/etc/fstab` and remounting. == User experience == Compression will result in file sizes (e.g. as reported by du) not matching the actual space occupied on disk. The [https://src.fedoraproject.org/rpms/compsize compsize] utility can be used to examine the compression type, effective compression ration and actual size. == Dependencies == Anaconda will need to be updated to perform the installation using <code>mount -o compress=zstd:1</code> == Contingency plan == * Contingency mechanism: will not include PR patches if not merged upstream and will not enable * Contingency deadline: Final freeze * Blocks release? No * Blocks product? No == Documentation == https://btrfs.wiki.kernel.org/index.php/Compression == Release Notes == Transparent compression of the filesystem using zstd is now enabled by default. Use the compsize utility to find out the actual size on disk of a given file. -- Ben Cotton He / Him / His Senior Program Manager, Fedora & CentOS Stream Red Hat TZ=America/Indiana/Indianapolis _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
