On sun, 27 Nov 2011 13:45:22 +0100, source wrote: > before sending this mail, i tried to track down previous messages from > the archive and found no similar entry. so either something went wrong > on my machine only or maybe there are too less testers around. > > about the real problem/bug : > > i tried to create several btrfs filesystems with success and tests about > performance and reliability but the free amount given to the system is > far too small, one example : > > #mkfs.btrfs -m raid0 -d raid0 /dev/sda8 /dev/sdb8 /dev/sdc8 > > WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL > WARNING! - see http://btrfs.wiki.kernel.org before using > > adding device /dev/sdb8 id 2 > adding device /dev/sdc8 id 3 > fs created label (null) on /dev/sda8 > nodesize 4096 leafsize 4096 sectorsize 4096 size 131.44GB > Btrfs Btrfs v0.19 > > # mkdir /test && mount /dev/sda8 /test > # df > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/md0 292911488 174222808 118688680 60% / > tmpfs 5120 4 5116 1% /lib/init/rw > tmpfs 611976 544 611432 1% /run > udev 10240 0 10240 0% /dev > tmpfs 1223952 76 1223876 1% /run/shm > /dev/md2 292833568 33312 292800256 1% /or > /dev/md1 292833568 202533276 90300292 70% /root/workplace > /dev/sdc1 90297 52782 32698 62% /boot > myon400:/ 976694528 485310720 491383808 50% /srv > /dev/sda8 137821156 28 90827392 1% /test > > in this case, you can see a raid0 setup for meta and data, also > acknowledged by "sdb8 id2" and "sdc8 id3", the overall amount > of 1k blocks in df = 137821156 but the available amount is > only 90827392 1-k blocks while 28 are in use. this looks like > the calculation of raid0 outputs something i would assume > for raid5 or in other words just 2 of 3 raid-members usable. > > maybe i misinterpreted something or made a mistake by creation > however any documentation around gave me no idea. This number is just a appraised number, not rigorous. It tells us how much space we can use to make up raid0 block groups which are used to store the file data. Thanks Miao > > this test was made on a debian sid, using btrfs v0.19. > > -- > 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 > -- 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
