Btrfs Sees Minor Performance Optimizations With Linux 6.12

[cynic]

I'd really like to see btrfs finally implement the originally promised hybrid (SSD+HDD) hot relocate feature. How hard could it be? The driver on a multi-disk FS has to decide where to place a new file anyway (on the SSD), while files of low interest (no recent read/writes) could be moved away to the HDD.

AFICT this is not actively worked on since years, unfortunately.

Also, this is not really that simple: you have to take in consideration when you have different profiles (RAID0, 1, C3, C4, 10) on mixed devices.
Moreover, there aren't only HDD and SDD in the storage world.

[ferry]

AFICT this is not actively worked on since years, unfortunately.

Also, this is not really that simple: you have to take in consideration when you have different profiles (RAID0, 1, C3, C4, 10) on mixed devices.
Moreover, there aren't only HDD and SDD in the storage world.

Sure, you can make it bigger. But there could be a minimal implementation, let's say, "single" on a hybrid of HDD and SSD. In that case the FS already needs to choose on which drive to place the file. How hard can it be to give a priority to the fastest drive.

Afaict there have been 3 different attempts, that got shot down. And then an excuse that it would be attempted via the VFS layer. A layered approach that lacks efficiency.

[gotar]

Actually BTRFS has 4 ways of setting compression

1. in fstab with the compress=zstd:level|lzo|zlib
2. with btrfs filesystem defrag -czstd object
3. with chattr +c object
4. with btrfs property set object compression zstd

That is way too many if you ask me, and I honesty think that only number 4 is the correct way of setting, changing or clearing the desired compression setting.

Surprisingly, method #4 cannot change compression level.

[waxhead]

Surprisingly, method #4 cannot change compression level.

Yeah , and this is kind of not what people expect. It only changes the property , it does not process the file at all (e.g. read/write everything) which is what you need to do if you want to change the compression method.

The current behavior is actually not that bad and far from insane , but it is not the behavior people expect.

[fong38]

Yeah , and this is kind of not what people expect. It only changes the property , it does not process the file at all (e.g. read/write everything) which is what you need to do if you want to change the compression method.

The current behavior is actually not that bad and far from insane , but it is not the behavior people expect.

I think they were referring to the actual compression level, meaning the number behind the compression algorithm to fine-tune the amount of compression applied. For instance zstd:6 or zlib:9. That only works with the fstab (force-)compress option.