On 22 November 2014 at 23:26, Marc MERLIN <m...@merlins.org> wrote: > > This one hurts my brain every time I think about it :)
I'm new to Btrfs so I may very well be wrong, since I haven't really read up on it. :-) > So, the bigger the -dusage number, the more work btrfs has to do. Agreed. > -dusage=0 does almost nothing > -dusage=100 effectively rebalances everything And -dusage=0 effectively reclaims empty chunks, right? > But saying saying "less than 95% full" for -dusage=95 would mean > rebalancing everything that isn't almost full, But isn't that what rebalance does? Rewriting chunks <=95% full to completely full chunks and effectively defragmenting chunks and most likely reduce the number of chunks. A -dusage=0 rebalance reduced my number of chunks from 1173 to 998 and dev_item.bytes_used went from 1593466421248 to 1491460947968. > Now, just to be sure, if I'm getting this right, if your filesystem is > 55% full, you could rebalance all blocks that have less than 55% space > free, and use -dusage=55 I realize that I interpret the usage parameter as operating on blocks (chunks? are they the same in this case?) that are <= 55% full while you interpret it as <= 55% free. Which is correct? -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
