On Wed, 8 Jul 2015 07:39:40 AM Brian May wrote:
My understanding though (from what was said yesterday) is that BTRFS with "RAID" support (currently) offers no guarantee that two copies of everything will be on separate disks. So if one disk fails, you could loose both copies of your data.
No, what happens with BTRFS RAID-1 is that you only get 2 copies of data on different device, no matter how many devices you have. So if you have a 3 drive RAID-1 using BTRFS then you will NOT have 3 identical mirrors; some data will be on device 0 & 1, some data will be on device 1 & 2 and some will be on device 0 & 2. https://btrfs.wiki.kernel.org/index.php/SysadminGuide#RAID_and_data_replicat... # With RAID-1 and RAID-10, only two copies of each byte of data are written, # regardless of how many block devices are actually in use on the filesystem. All the best, Chris -- Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC