about ctdb data replication

[Andrew Bartlett]

On Thu, 2013-03-14 at 21:59 +1100, Amitay Isaacs wrote:
> On Thu, Mar 14, 2013 at 8:32 PM, Liujun (A) <liujun09 at huawei.com> wrote:
> 
> > I know ctdb has a ltdb(local tdb) on each node , is the global db must
> > store on share filesystem（like gfs）,which all node can write and read from
> > the global db.
> >
> 
> CTDB does not need the databases to be stored in the shared storage. In
> fact it is designed such that the databases on each node are independent.
> 
> 
> > Another questions is if the same data are stored in each node for data
> > recovery?
> >
> 
> Recovery process will merge all the databases and then push them to all the
> nodes. So after recovery all the databases will be exact replica on all the
> nodes.  Persistent databases are always in sync (that is they are always
> the same across all the nodes). Non-persistent databases can change
> independently on all the nodes and do not need to be synchronized.

Does CTDB need shared storage at all, except for the actual data files?

Could you use CTDB for a HA solution that (electronically) unplugged the
disks from one node, and plugged them into another node, avoiding the
need for a cluster FS?  (Naturally with logic to ensure that clients
could not talk to the node without the disk attached)

Andrew Bartlett

-- 
Andrew Bartlett                                http://samba.org/~abartlet/
Authentication Developer, Samba Team           http://samba.org