> If I recall correctly, CentOS and RHEL will use the device-mapper driver by default and CoreOS the btrfs CentOS & RHEL uses device-mapper with loopback devic

> If I recall correctly, CentOS and RHEL will use the device-mapper driver by default and CoreOS the btrfs CentOS & RHEL uses device-mapper with loopback device by default (and logs "Usage of loopback devices is strongly discouraged for production use. Either use --storage-opt dm.thinpooldev or use --storage-opt dm.no_warn_on_loop_devices=true to suppress this warning". Also related article [1] CoreOS uses overlayfs by default now from a while [2] [1] http://www.projectatomic.io/blog/2015/06/notes-on-fedora-centos-and-docker-storage-drivers/ http://www.projectatomic.io/blog/2015/06/notes-on-fedora-cen... [2] https://lwn.net/Articles/627232/ https://lwn.net/Articles/627232/