The Anaconda installer in Fedora 45 will introduce a new option for storage configuration: Stratis, a modern solution for local storage management.
Stratis isn’t a completely new technology, it uses existing tools and technologies like device mapper, LUKS, and XFS and integrates them into an easy to use package. The idea is to provide modern storage features while hiding the often complex logic behind them. Adding support to the installer brings these features even closer to Fedora users.
There are only two basic structures or layers you need to know when working with Stratis: pools and filesystems. Pools represent an abstract layer on top of existing block devices (disks, partitions, RAID arrays etc.). A pool can consist of one or more devices (for systems with multiple disks, for example). Features like encryption or over-provisioning are also configured on the pool level. Multiple filesystems can be created on the pool. These are devices that will serve as your root or home volumes. Some additional features supported by Stratis include snapshots, caching, and for encrypted pools, multiple unlocking methods like TPM or Clevis/Tang. Caching and encryption without a passphrase are not currently supported by Anaconda, but these can be easily enabled after the installation.
Management of Stratis devices can be done using the stratis command. For more information, check our older, but still valid, article Getting started with Stratis or the Stratis project how-to.
Installation using Web UI
The new web-based user interface for the Anaconda installer currently doesn’t allow selecting which type of storage technology will be used for the automated and guided partitioning options. The storage layout you will get depends on the Fedora variant you choose to install. But if you want to use Stratis, you still have an option in the graphical installation. Any storage layout can be created manually using the Cockpit storage module, which is integrated into the installer. To enter it, simply select the If none of the options above apply… option on the Installation Destination step.
The Cockpit storage module supports a wide variety of storage configurations and Stratis is one of the supported technologies. Do not forget that with manual partitioning, you need to create all required partitions so first create partitions required for booting (/boot and /boot/efi or biosboot, based on your system configuration). After that, simply create a new Stratis pool from the menu.
Creating stratis pool
After selecting a name for the pool and the disk (or disks) it will be placed on, you can decide whether to enable encryption and over-provisioning for the pool. Over-provisioning allows allocation of more space for the filesystems created on the pool. Similarly to how LVM thin provisioning and Btrfs work. With over-provisioning enabled, there is no need to worry about running out of space in root with still plenty of free space in /home. It also allows greater flexibility when using snapshots. On the other hand, you actually need to be aware that you don’t really have terabytes of space and you need to make sure you won’t actually run out of space on your disk. Both encryption and over-provisioning can also be enabled or disabled after the installation.
Creating stratis filesystems
With the new pool created, you now need to add some filesystems to it. You’ll most likely want the standard two separate filesystems for your / and /home. But you can also create a separate filesystem for your /var, for example.
If you enable over-provisioning on your pool, you can also decide to not specify sizes for the filesystems and use the 1 TiB default size with over-provisioning or set a size limit for the filesystem to prevent it from automatically growing if you ever run out of space.
Using the configured layout
With all the filesystems created, you can Return to installation. Anaconda will check the created devices to make sure all requirements are met and return you to the Installation destination page where a new Use configured storage option will be preselected with the devices that were just created.
That is the storage part of the installation done. You can double-check on the Review and install page that everything is correctly set and start the installation.
Installation using kickstart
For advanced users who wish to use automated installations, full kickstart support for Stratis is also available. Both automatic and manual partitioning are available via kickstart.
Automatic partitioning is simple: the existing autopart command can be used with –type=stratis to create the default Stratis storage layout fully automatically. A storage section in kickstart, for setting up an encrypted Stratis layout, could look like this:
zerombr
clearpart --all --initlabel
autopart --type=stratis --encrypted --passphrase="passphrase"
Manual partitioning requires building the entire storage layout manually from bottom up. Two new Stratis kickstart commands were added: stratispool for creating and managing Stratis pools and stratisfs for creating and managing Stratis filesystems. Usage of these commands and most of the options are similar to how kickstart partitioning works with LVM. An example of a more advanced Stratis layout can be found below.
reqpart
part /boot --fstype=ext4 --size=500
part stratis.01 --size=1 --grow --ondisk=vda
part stratis.02 --size=1 --grow --ondisk=vdb
stratispool fedora stratis.01 stratis.02
stratisfs / --name=root --poolname=fedora --size=5000 --grow
stratisfs /home --name=home --poolname=fedora --size=1 --grow
Here we are creating a pool called fedora on top of two disks, vda and vdb, with two filesystems. One called root for / and a second called home for /home. The –grow tells the installer to use all available free space when creating the devices. For more details about the commands see the kickstart documentation.
Conlusion
The newly introduced Stratis support in Anaconda offers an easy way to take advantage of the modern storage features offered by Stratis. With the Web UI support available through Cockpit storage, you can now easily use Stratis on your system. We plan to simplify the process even more in future releases and enable even more advanced Stratis features.
If you run into any issues or have feedback, both the Anaconda and Stratis teams would love to hear from you.
