On Wed, Feb 24, 2021 at 11:10 PM Amy Parker <enbyamy@xxxxxxxxx> wrote: > > The compression options in Btrfs are great, and help save a ton of > space on disk. Zstandard works extremely well for this, and is fairly > fast. However, it can heavily reduce the speed of quick disks, does > not work well on lower-end systems, and does not scale well across > multiple cores. Zlib is even slower and worse on compression ratio, > and LZO suffers on both the compression ratio and speed. > > I've been laying out my plans for a backup software recently, and > stumbled upon LZ4. Tends to hover around LZO compression ratios. > Performs better than Zstandard and LZO slightly for compression - but > significantly outpaces them on decompression, which matters > significantly more for users: > > zstd 1.4.5: > - ratio 2.884 > - compression 500 MiB/s > - decompression 1.66 GiB/s > zlib 1.2.11: > - ratio 2.743 > - compression 90 MiB/s > - decompression 400 MiB/s > lzo 2.10: > - ratio 2.106 > - compression 690 MiB/s > - decompression 820 MiB/s > lz4 1.9.2: > - ratio 2.101 > - compression 740 MiB/s > - decompression 4.5 GiB/s > > LZ4's speeds are high enough to allow many applications which > previously declined to use any compression due to speed to increase > their possible space while keeping fast write and especially read > access. > > What're thoughts like on adding something like LZ4 as a compression > option in btrfs? Is it feasible given the current implementation of > compression in btrfs? This is definitely possible. I think the only reason lz4 isn't enabled for Btrfs has been the lack of interest in it. I'd defer to some of the kernel folks (I'm just a user and integrator myself), but I think that's definitely worth having lz4 compression supported. -- 真実はいつも一つ！/ Always, there's only one truth!
