On Thu, Jan 31, 2013 at 08:21:50AM +1100, Robert Mueller wrote: > > For that matter, one big question I have is why each of these results is > so different. > > [robm@imap14 conf]$ for i in 1 2 3 4 5 6 7 8 9 10; do fallocate -l 20m > testfile3; filefrag testfile3; /bin/rm testfile3; done The most likely reason is that it depends on transaction boundaries. After a block has been released, we can't reuse it until after the jbd2 transaction which contains the deletion of the inode has committed. So even after you've deleted the file, we can't reuse the blocks right away. The other thing which will influence the block allocation is which block group the last allocation was for that particular file. So if blocks become available after a commit completes, if we've started allocating in another block group, we won't go back to the initial block group. Cheers, - Ted -- 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
