Red Hat Summit21장. Setting up Stratis file systems
Stratis is a local storage-management solution for Red Hat Enterprise Linux. It is focused on simplicity, ease of use, and gives you access to advanced storage features.
Stratis runs as a service to manage pools of physical storage devices, simplifying local storage management with ease of use while helping you set up and manage complex storage configurations.
Stratis can help you with:
- Initial configuration of storage
- Making changes later
- Using advanced storage features
The central concept of Stratis is a storage pool. This pool is created from one or more local disks or partitions, and file systems are created from the pool. The pool enables features such as:
- File system snapshots
- Thin provisioning
- Caching
- Encryption
21.1. Components of a Stratis file system
Stratis consists of three main components that work together to provide advanced storage management: block devices, storage pools, and file systems. These components enable thin provisioning, snapshots, and automatic space management.
Externally, Stratis presents the following file system components on the command line and through the API:
blockdev- Block devices, such as disks or disk partitions.
poolComposed of one or more block devices.
A pool has a fixed total size, equal to the size of the block devices.
The pool contains most Stratis layers, such as the non-volatile data cache using the
dm-cachetarget.Stratis creates a
/dev/stratis/my-pool/directory for each pool. This directory contains links to devices that represent Stratis file systems in the pool.filesystemEach pool can contain zero or more file systems. A pool containing file systems can store any number of files.
File systems are thinly provisioned and do not have a fixed total size. The actual size of a file system grows with the data stored on it. If the size of the data approaches the virtual size of the file system, Stratis grows the thin volume and the file system automatically.
The file systems are formatted with the XFS file system. Stratis utilizes the XFS file system for its storage, and provisions a Stratis volume.
A Stratis volume will be referred to as a “Stratis filesystem" throughout the rest of the documentation to retain alignment with the command line interface.
Stratis tracks information about file systems that it created which XFS is not aware of, and changes made using XFS do not automatically create updates in Stratis. Users must not reformat or reconfigure XFS file systems that are managed by Stratis.
Stratis creates links to file systems at the /dev/stratis/my-pool/my-fs path.
Stratis uses many Device Mapper devices, which appear in dmsetup listings and the /proc/partitions file. Similarly, the lsblk command output reflects the internal workings and layers of Stratis.
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