Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
/ 2004-07-02 17:16:31 -0400 \ Greg Freemyer: > I'm not a DRBD expert, but I do know snapshots and advanced backup > strategies. > > Maybe you could use DRBD to create "snapshots"? They are often used to > provide read-only copies of volumes for backup/testing/data mining/load > sharing. have a look at the thread(s) about drbd and lvm and snapshots a few weeks ago. > In particular if backups are your only issue, maybe you could do > something like the below: > > 1) Quiese application on primary > 2) Flush filesystem cache to disk and stop filesystem i/o > 3) stop drbd replication from master to secondary. > 4) re-enable filesystem i/o > 5) Allow application to restart > 6) On secondary mount drbd volume read-only > 7) On secondary perform backup > 8) On secondary unmount drbd volume > 9) restart drbd replication > > Comments: > step 1) This is commonly required with snapshots, so it should be fairly > easy. Typically databases etc. have way to signal them to prepare for > snapshot. > > step 2) I know XFS supports the filesystem i/o freeze/unfreeze concept > form user-space. I'm not sure about others. > > step 3) I'm not a drbd expert, but I assume this is easy on_secondary# /etc/init.d/drbd stop > step 9) With drbd 0.7, only the dirty blocks should need to be copied > between the servers, so the load should not be too bad. on_secondary# /etc/init.d/drbd start as long as the primary stays up, 0.6 does a "SyncingQuick", too. lge