Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Hi! > -at backup time (2AM?): > -stop drbd and heartbeat on the secondary > -bring down the dedicated eth1 connection to the primary > (leaving eth0 still up so I can get in if need be) No need for that. When drbd is stopped it doesn't matter if your replication link is up or not. > -mount the sda4 partition (NOT the drbd0 device as drbd will be > stopped) to it's normal position Here is a crucial point. You should at least remount the filesystem on the primary read-only - to prevent your filesystem's metadata AND the actual data from being corrupted because you pulled the plug in the wrong moment. > -run my usual tape backup routine > -unmount sda4 again > -bring eth1 back up see above > -start drbd and heartbeat again This should work. > I am thinking that in this way my users will still see NO downtime > of the primary resource (unless of course there is a hardware > failure during the tape backup while the secondary is offline!), and > I still get a tape backup that is quite current. Your assumtions seem to be correct to me. > Could it really be this simple? We don't use lvm at all, just plain > old ext3 file systems, so I believe this negates the whole lvm > snapshot and then back that up dicussion I have seen here in the > lists. What are your thoughts? Currently we implement I don't understand why you seem to insist on going the complicated way when you can have this which significantly lower downtime just by using lvm and snapshots. (disks <-> LVM <-> DRBD) With using lvm on both ends you could even run your tape backup from the primary or the secondary (important if you have a hardware failure and can't replace the machine in less than one day) without modifying anything on your setup. cheers, juergen