On 16/06/2010 21:35, Freddie Cash wrote:
<snip a lot of fancy math that missed the point> That's all well and good, but you missed the part where he said ext2 on a 5-way LVM stripeset is many times faster than btrfs on a 5-way btrfs stripeset. IOW, same 5-way stripeset, different filesystems and volume managers, and very different performance. And he's wondering why the btrfs method used for striping is so much slower than the lvm method used for striping.
This could easily be explained by Roberto's theory and maths - if the lvm stripe set used large stripe sizes so that the random reads were mostly read from a single disk, it would be fast. If the btrfs stripes were small, then it would be slow due to all the extra seeks.
Do we know anything about the stripe sizes used? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
