Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Lars Ellenberg wrote: > / 2004-04-07 21:09:32 +0200 > \ Andreas Semt: >>nodeA (Heartbeat and drbd active), nodeB (Heartbeat and drbd standby). >>To make a clean and consistent snapshot i will do following (all on nodeB!): >>a) stop heartbeat (at 02.00 pm per cron for example), i.e. that means >> for heartbeat: "nodeB is dead!, i am the only one left!" >>b) -> result: no further drbd mirroring will be done, the master is >> still the master (nodeA), nodeA and nodeB knows nothing from each >> other > > > What makes you think so? nodeB is down, cause i shut down heartbeat on nodeB. I thought heartbeat is aware of this, only nodeA left. Okay, incorrect again. > [snip] > > >>Pro: nodeA is still active / services are online >>Con: How to say drbd that is will be shut down in 5 minutes (it is 01:55 >>pm, heartbeat/drbd shutdown at 02:00 pm)? Does exists a command for drbd >>to say: "In five minutes you will lost your connection to your primary >>partner, so please write all the stuff in the buffer (of nodeA >>(primary)) and then disconnect and stay on your own"? or to say to the >>primary partner: "Please write all your pending data (from the buffer) >>to your partner (in secondary state), cause that is the last chance if >>you won't like the idea of inconsistent data between you and your partner"? > > > You keep suggesting the same thing again and again. I try not to do so. Really! > No. And, DBRD does not do any buffering. Mhm ... why there is a option "-S, --sndbuf-size size", from the drbdsetup man page: --- snip --- The socket send buffer is used to store packets sent to the secondary node, which are not yet acknowledged (from a network point of view) by the secondary node. --- snap --- > It is the file system (that is the mounted file system instance on the > DRBD primary node), that needs to be notified, and there currently just > is no way to do so in a sensible manner. One need to hack up some > existing or new tools, and probably the drbd api too, for this to work. > Could be done. Probably won't be too complicated. Just takes some time > to do it the right way, and nobody has done this so far. Perhaps that is a challenge ... sometime ;-) That is my lack of understanding: What happens with nodeB if the heartbeat AND drbd connection to nodeA (who is Master/primary) get lost? Can I do anything useful with nodeB (and the data on it) or means that for heartbeat/drbd "nodeB is completely broken, repair it!"? Because the situation stated below can happen, or not? -------- ------- | | ethernet / serial wire | | | nodeA | ---------------------------/ /--------------- | nodeB | | | | | ------- ------- Thanks (again) for helping me understanding all that stuff! -- Best regards, Andreas Semt