The upcoming Linux 6.2 kernel should feature improved file system handling, including performance improvements for SD cards and USB sticks, as well as FUSE. As for next-gen storage subsystems… not so much.
For a mature OS kernel, significant improvements are still being made in how Linux handles existing disk formats, and this should improve when kernel 6.2 comes out sometime in early 2023.
A patch by Sony engineer Yuezhang Mo speeds up the creation of new files or directories on an exFAT disk with many files on it – and the more files there are, the greater the improvement. This follows the earlier patch by the same programmer to improve exFAT handling in March.
After Microsoft released the exFAT specification in 2019 and included it in the Linux kernel in 2020, support has steadily improved. Only recently has Linux gained the ability to repair exFAT volumes thanks to a patch by Samsung developer Namjae Jeon, which manages the out-of-tree exFAT drive for old kernels like the one used in Android. Its commit history shows many contributions from the Sony programmer. Another Samsung engineer, Jaeguk Kim, contributed a patch to improve F2FS, the Flash Friendly File System.
The former Ubuntu and current Microsoft engineer Christian Brauner was also busy. He sent in a detailed patch to add a dedicated VFS API for POSIX ACLs. These have been supported for a long time, as you can see from this feature description from 2002, but the new release aims to clean up and simplify their handling. Brauner also submitted a patch to support ID mapped mounts for SquashFS volumes. This is a follow-up to his earlier patch that introduced ID-mapped mounts, which also includes an explanation of how they work and what they’re for.
There are also improvements to some of the more established file systems. One of them is a list of fixes and improvements for XFS, targeting the important new feature of online repair. Another patch brings performance improvements for volumes mounted with FUSE – ie where the filesystem code runs in a userspace program, not as part of the kernel. There are even some bug fixes for the now venerable ext4.
There are also some improvements in Btrfs, particularly in handling RAID 5 and 6. In particular, a patch addresses the “destructive read-modify-write” problem for Btrfs RAID5 arrays (but not RAID6). That’s a good thing, but these disk layouts are still not recommended. In the words of the product’s own documentation:
The feature should not be used in production, only for evaluation or testing purposes.
Of course, since this is a FOSS file system for a FOSS operating system, there are workarounds for this, e.g. B. using the integrated Linux kernel
mdraid support over the
mdadm command to create a RAID 6 volume, and then format it with Btrfs. Our story about upgrading what may be the oldest Debian installation mentioned running LVM on RAID on LVM. It’s possible and people do it, but that doesn’t mean it’s a good idea unless you’re an ascended Linux elder.
Simplifying and integrating this type of complex disk configuration is exactly what next-generation filesystems should deliver, but while code changes continue to trickle in, two of the most important have gone relatively quiet.
While Ubuntu continues to maintain its ZSys code, there isn’t much activity. It’s worth noting that there hasn’t been a new post on the ZSys blog since the Ubuntu 20.04 timeframe, and some users are starting to wonder what’s happening and whether it should be removed.
This is certainly not due to the lack of development of OpenZFS, which released version 2.1.7 earlier this month with many updates and support for up to Linux 6.0. There are also active and innovative external tools using it, such as B. ZFSBootMenu. It’s also supported in NixOS, the innovative distro we talked about last week.
On the Red Hat side, the Stratis team released version 3.4 in November and have had three minor point releases since then. However, the changelog does not show very significant work. For example, it still targets the version of Fedora before the current one. You can use it in RHEL 9, but it remains an unsupported technical preview like it was in RHEL 8 in 2019.
We could be wrong, but it looks to us like both Canonical and Red Hat have lost interest in pushing this innovative technology forward. We’d love for someone else to pick up on the projects, integrate and improve on them like some Android vendors are doing with exFAT. It appears to be a huge opportunity for companies developing their own Ubuntu-based distributions like Linux Mint and ZorinOS, which address perceived weaknesses of the mainline desktop product. ®
https://www.theregister.com/2022/12/20/kernel_62_fs_improvements/ Kernel 6.2 promises several file system improvements • The Register