On 2011-06-18, at 11:00 AM, Greg Freemyer <greg.freemyer@xxxxxxxxx> wrote: > On Sat, Jun 18, 2011 at 3:19 AM, Andreas Dilger <aedilger@xxxxxxxxx> wrote: >> I was thinking about this, and am wondering if it makes sense to have an absolute score for fragmentation instead of a relative one? >> >> By absolute I mean something like fragments per MB or similar. A bad score might be anything > 1. For files smaller than 1 MB in size it would scale the ratio to the equivalent if the file was 1MB in size (e.g. a 16kB file with 4 fragments would have a score of 256, which is clearly bad). Large files can have a score much less than 1, which is good. >> >> Cheers, Andreas > > Shouldn't be based on fragments per max extent size for ext4? > > And I think the max extent size for a 4KB page is 128 MB, right? I was thinking about that, but in most cases it is unrealistic that all files have 128MB extents except on empty test filesystems, and I don't think that files with "only" 32MB extents should be considered that badly off. I don't particularly care what the exact scale is, but I like the idea of an absolute measure instead of a relative measure (i.e. 33% fragmented). Cheers, Andreas-- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
