On Wed, Apr 22, 2020 at 11:58:41AM +0200, Stefanie Leisestreichler wrote: > Hi. > I might be a first time user with btrfs for a new system I will set up. > > Just want to make sure: As I read the docs, the note about RAID 1 and that > there will be no redundant data is true only, if the RAID, which is > possible, is set up to use only 1 physical device, right? You can't set up btrfs RAID-1 to use only one device. It's only possible to end up like that if you set up a 2-device RAID-1 and then unplug a device and mount it in degraded mode. > If RAID 1 using btrfs is defined to use two seperate disk, say /dev/sda2 and > /dev/sdb2, I will have the same redundancy like using md. Is this correct? You'll have two copies, so one device redundancy, regardless of the number of devices. Traditional RAID-1 will use as many copies as devices; btrfs RAID-1 is two copies. (Although there are 3-copy and 4-copy variations in the latest kernels). Hugo. -- Hugo Mills | You can play with your friends' privates, but you hugo@... carfax.org.uk | can't play with your friends' childrens' privates. http://carfax.org.uk/ | PGP: E2AB1DE4 | C++ coding rule
