On 6/30/05, Jonathan E Brassow <jbrassow@xxxxxxxxxx> wrote: > > On Jun 30, 2005, at 10:13 AM, Greg Freemyer wrote: > > > On 6/29/05, Jonathan E Brassow <jbrassow@xxxxxxxxxx> wrote: > >> This patch defines a couple more states that logs can return, and > >> checks for those states in the mirror code. The states are useful for > >> logs that have cluster support. > >> > >> brassow > > > > Have I been asleep? This is the first I heard of DM having cluster > > mirror support. I assume the goal is something along the lines of > > what DRBD provides. > > > > Can someone give a very high-level overview of current status, plans, > > etc. related to DM Cluster Mirror support. And if this related to the > > DRBD project? > > Please note that the "mirroring [patch x of 8]..." set for device fault > tolerance has been replaced with the "mirroring [patch x of 6]..." set. > > The cluster mirroring that I'm talking about is active/active and > capable of handling more than 2 nodes. It would be used in conjunction > with a clustered file system - like GFS. The application sitting on > the cluster mirror should be cluster-aware. You wouldn't be able to > just put ext3 on there and expect it to work in a cluster capacity. > > Although there are some minor things that need to happen in the mirror > proper code (as can be seen from the smallness of the cluster patch), > the heavy lifting is done by a cluster-aware log. That is were you are > keeping track of clean/dirty/recovering state. > > An out-dated (but still useful for background) dock can be found at > http://www.brassow.com/mirroring/index.html > > brassow > Sounds like you have more ambitious plans than DRBD. (They have active-passive now and IIRC they plan the next major release to have active-active, but I think only on 2 nodes.) Is the GFS team planning on supporting this infrastructure. I hope so. Greg -- Greg Freemyer The Norcross Group Forensics for the 21st Century
