OverlayFS On Linux 5.15 Improves Performance, Copies Up More Attributes

[phoronix]

Phoronix: OverlayFS On Linux 5.15 Improves Performance, Copies Up More Attributes

OverlayFS continues to be used by Linux IoT/embedded devices and other use-cases as a union mount file-system. With Linux 5.15 the OverlayFS file-system continues to improve...

https://www.phoronix.com/scan.php?page=news_item&px=Linux-5.15-OverlayFS

[skeevy420]

It can also be nice for game modding. You can do all your modding on the overlay so you don't have to waste space with multiple copies of games.

Though it doesn't always work as simple as it sounds (uptight launchers, DRM, or whatnot) and it's a lot easier to copy paste games. Frankly, I haven't bothered in a good while since I use a large HDD for storage and an SSD or NVMe for the OS and whatever I'm playing (if it'll really benefit from the extra speed...some games ain't worth 100 high-speed gigabytes to load a few seconds faster).

[NobodyXu]

It can also be nice for game modding. You can do all your modding on the overlay so you don't have to waste space with multiple copies of games.

Though it doesn't always work as simple as it sounds (uptight launchers, DRM, or whatnot) and it's a lot easier to copy paste games. Frankly, I haven't bothered in a good while since I use a large HDD for storage and an SSD or NVMe for the OS and whatever I'm playing (if it'll really benefit from the extra speed...some games ain't worth 100 high-speed gigabytes to load a few seconds faster).

Btrfs has builtin CoW support.

Just cp with —reflink=auto, it should create a reference to the original blocks in a CoW manner, without mounting filesystem or any sudo.

Or you can create a snaoshot, which does need sudo, but it can be taken at any time and might be easier to manage.

Edit:

Or you can consider XFS, it also supports reflink, have awesome performance comparable to ext4 and sometimes even have better performance and is universally available just like ext4 and overlayfs.

[skeevy420]

Btrfs has builtin CoW support.

Just cp with —reflink=auto, it should create a reference to the original blocks in a CoW manner, without mounting filesystem or any sudo.

Or you can create a snaoshot, which does need sudo, but it can be taken at any time and might be easier to manage.

I use reflinks on my BTRFS root and deduplication on the ZFS mirror my games are on. They're just tools at our disposal with features that are file system dependent so it's not like they're "better" solutions in regards to saving space or doing modifications while leaving the underlying files intact when compared to something that's universally available like OverlayFS

[NobodyXu]

I use reflinks on my BTRFS root and deduplication on the ZFS mirror my games are on. They're just tools at our disposal with features that are file system dependent so it's not like they're "better" solutions in regards to saving space or doing modifications while leaving the underlying files intact when compared to something that's universally available like OverlayFS

While Btrfs and ZFS aren’t as universally available as overlayfs, I do consider it to have some advantages of overlayfs:
- You don’t have to manually mount overlayfs everytime you want to run a modified game
- Btrfs and ZFS’s CoW is block wise, while overlayfs’s CoW is file wise.
Meaning if you modify a large file, overlayfs would copy the whole file into upper dir (include dir containing it)
- Lookup takes longer

Another alternative to Btrfs and ZFS is XFS.

It’s just as popular as ext4, but also supports reflink and has awesome performance comparable to ext4, sometimes even better performance than ext4.

[skeevy420]

Another alternative to Btrfs and ZFS is XFS.

It’s just as popular as ext4, but also supports reflink and has awesome performance comparable to ext4, sometimes even better performance than ext4.

For the longest time that was my go-to file system, like 2005 to 2015. At the end of the day I prefer using a file system with fast compression/decompression like LZ4 and Zstd so I'm more likely to go with BTRFS, ZFS, or F2FS these days.

But OverlayFS is, IMHO, something that you'd want to use in modding tools because it's Linux-universal...where you tell the GUI this is where the game is and the tool would handle everything from there. I agree that doing it all manually isn't easy.