On Thu, Jan 05, 2012 at 10:21:57AM +0100, Fabian Zeindl wrote: > Hi, > > the subject is pretty selfexplanatory. I"m creating a btrfs using > > sudo mkfs.btrfs -m raid1 -d raid1 <smalldisk> <largedisk> > > it creates the fs, apparently with the size of the larger disk, no matter in which order i supply the disk-arguments. > How can this be correct? Because btrfs doesn't actually do "RAID-1" (in the sense that blocks with the same address on the two disks have identical contents). You should probably read the mis-named "Sysadmin's Guide" on the wiki[1], which explains what btrfs actually does with its replication. You should also probably read the FAQ entries on free space[2], since using plain "df" for btrfs is usually misleading. > Is there some way like "cat /proc/mdstat" to see what btrfs is doing and to assure myself my raid1 is secure? It's not > terribly important data, hence i'm trying btrfs, but i don't want to lose it either. You could run a scrub, which will verify all of the data mirrors on the volume, and fix anything that's not redundant. Hugo. [1] http://btrfs.ipv5.de/index.php?title=SysadminGuide [2] http://btrfs.ipv5.de/index.php?title=FAQ#Why_does_df_show_incorrect_free_space_for_my_RAID_volume.3F -- === Hugo Mills: hugo@... carfax.org.uk | darksatanic.net | lug.org.uk === PGP key: 515C238D from wwwkeys.eu.pgp.net or http://www.carfax.org.uk --- vi: The core of evil. ---
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