EXT4 In Linux 3.8 Brings Inline Data, Seek Hole/Data

[phoronix]

Phoronix: EXT4 In Linux 3.8 Brings Inline Data, Seek Hole/Data

The EXT4 file-system pull request for the Linux 3.8 kernel has been submitted and it's bringing fixes plus introduces two new features...

http://www.phoronix.com/vr.php?view=MTI1NTA

[oleid]

This data inlining feature will probably be a great win for gentoo users storing the portage tree in an ext4 filesystem.

[oliver]

Not sure about a 'great' win, as 256 bytes won't allow for much ebuild data, but yes, it could win some bytes.

Having said that, does it require a disk-format change? And if so, is it doable with tune2fs or will a full mkfs.ext4 be required?

[oleid]

Not sure about a 'great' win, as 256 bytes won't allow for much ebuild data, but yes, it could win some bytes.

I assumed the inodes to be larger, but you're right. The default inode size is 256 bytes.

We can probably save no more than 46 MB:

The total size of files smaller than 256 byte:

find -type f -size -256c | awk '{size+=$7}; END {print size}'
2033425

Total number of files smaller than 256 byte:

find -type f -size -256c | wc -l
12205

So in the best case 12205 files won't use 4kB blocks each, but no additional size.

[oliver]

I'd be more interested in the performance boost this gives on 'emerge' commands going through the tree.

That said, will we have to reformat?