Sorry I forgot to post that, -> btrfs fi show Label: none uuid: 2feccf06-5af8-4d8a-ad8d-a090cf4ef69a Total devices 2 FS bytes used 16.54GB devid 1 size 40.90GB used 14.04GB path /dev/sda7 devid 2 size 17.75GB used 14.03GB path /dev/sda6 The array is more of a for-fun and testing thing than a real world example. I've simply combined two differently sized partitions on the same disk together. So how much space is actually used now? On Fri, Mar 29, 2013 at 3:12 PM, Josef Bacik <jbacik@xxxxxxxxxxxx> wrote: > On Fri, Mar 29, 2013 at 07:58:40AM -0600, Harald Glatt wrote: >> Hi, >> >> I'm somewhat confused with who is right on what when it comes to >> showing disk usage and space free. >> >> I have a file system that I'm using for testing with a full linux >> installed as well as X and a desktop. I've created a good amount of >> snapshots and I've also done a lot of changes to the system throuhgout >> the process. >> >> I've run a balance before taking these meassurements: >> >> -> df -h reports 59G total space, 18G used, 7G free. >> -> btrfs fi df / reports the following: >> Data, RAID0: total=16.00GB, used=15.58GB >> System, RAID1: total=32.00MB, used=4.00KB >> System: total=4.00MB, used=0.00 >> Metadata, RAID1: total=6.00GB, used=974.36MB >> >> So from what I garther the df reports used space somewhat correctly. >> Is it true that my total disk usage should only be around 16.6G now? >> Does that include all space required to store the snapshots as well? >> I'd be pretty amazed at that number because I've changed A LOT between >> snapshots. >> >> Why is df reporting only 7G free? Wouldn't it be possible to make it >> report the sum of total minus used instead which would be at least a >> lot closer to the truth? >> > > So you need to include btrfs fi show to get at why df -h reports what it > reports. Basically df does this > > total = total bytes > used = total data used * raid multiplier + total system used * raid multiplier + > metadata used * raid multiplier > avail (or free) = (data total - data used) + (total bytes - allocated) > > where allocated is the sum of all the data chunks * their raid multipliers. How > many disks do you have in this array? Take whatever that number is and multiply > it by the numbers for the RAID1 chunks and thats how much real space is used. > Thanks, > > Josef -- 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
