Hi John, On Thu, Oct 9, 2014 at 10:44 AM, John R Pierce <pierce at hogranch.com> wrote: > On 10/9/2014 10:39 AM, Jason T. Slack-Moehrle wrote: > >> I need to keep 2 systems identical. Mostly e-mail directories, web >> directories, mysql, etc. The goal here is to have a 2nd system ready to go >> it the first one starts to exhibit hardware issues. >> >> What are options to have this happen? I'm going out on a limb and thinking >> rsync but I haven't used it past just simple use cases. >> >> Can anyone provide some insight for me? >> > > drbd is the live replication system, this does block level replication of > logical volumes. rsync doesn't handle changing-on-the-fly stuff very > well, especially stuff like a database file system which is undergoing > constant random write activity. > > but note, the drbd slave copy can't be mounted until drbd is stopped, or > all heck breaks loose. Just to clarify. What state is the slave in? If master goes down, how does the slave become active? Just reboot it and let it come up? The wording "slave copy can't be mounted until drdb is stopped" leads me to believe the slave is in some alternate state to be receiving the blocks of data.