On Thu, Feb 25, 2021 at 1:23 PM Neal Gompa <ngompa13@xxxxxxxxx> wrote: > > 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. This has been brought up over and over for many years: https://btrfs.wiki.kernel.org/index.php/FAQ#Will_btrfs_support_LZ4.3F Things have to be evaluated in btrfs' context, i.e. how it uses compression. More details there anyway. > > > > -- > 真実はいつも一つ！/ Always, there's only one truth! -- Filipe David Manana, “Whether you think you can, or you think you can't — you're right.”
