Upstream docker is moving to overlay2 by default for its storage. We plan on following suit. Their are some performance advantages of overlay2 over devicemapper in memory sharing, which we would like to take advantage of. We now have SELinux support for Overlay file systems, so the security should be just as good.
Note: Overlay is not a Posix Compliant file system, so their could be problems with your containers running on overlay, so we want to make sure it is fairly easy to switch back to devicemapper. Devicemapper out of the box, on Fedora Workstation, currently defaults to loopback devices for storage, which has a performance penalty, but this was the only way we were able to get docker to work right away. Switching to overlay2 will cause the storage to be shared with / and will eliminate this performance overhead. This is the way we will ship Fedora Workstation. On Fedora atomic host and Fedora server we have been storing devicemapper storage on a separate partition. We plan on doing the same thing with overlay2. This means separate device will be mounted on /var/lib/docker. This will make it easier for someone to switch back to devicemapper, if overlay2 has problems. Upgraded systems will not be effected. If you want to switch from one storage to another take a look at the `atomic storage` commands. We will write up release notes to cover this change. Along with a blog explaining the commands to switch back and forth. _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org
