[求助]怎样增加debian lenny对ext4的支持

tuzi737

Post by d00m3d;1933021
严格来说：不能！

如不使用 ext4 独有的 extents，ext3 仍可以挂成 ext4 使用，可是 extents 才是提升效能的精髓所在。。。

我的意思不是挂载而是直接转换，就像ext2->ext3那样。

BTW，能否扫盲一下，那个extents大致有什么好处，怎么提升效能的。

zyl19861126

Extents

The traditionally Unix-derived filesystems like Ext3 use a indirect block mapping scheme to keep track of each block used for the blocks corresponding to the data of a file. This is inefficient for large files, specially on large file delete and truncate operations, because the mapping keeps a entry for every single block, and big files have many blocks -> huge mappings, slow to handle. Modern filesystems use a different approach called "extents". A extent is basically a bunch of contiguous physical blocks. It basically says "The data is in the next n blocks". For example, a 100 MB file can be allocated into a single extent of that size, instead of needing to created the indirect mapping for 25600 blocks (4 KB per block). Huge files are split in several extents. Extents improve the performance and also help to reduce the fragmentation, since a extent encourages continuous layouts on the disk.

http://kernelnewbies.org/Ext4

blue_stone

也不知道2.6.28什么时候才能进入sid