Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 09/23/11 22:20, Arnold Krille wrote: > On Friday 23 September 2011 21:37:51 you wrote: >> On 09/23/11 19:03, Arnold Krille wrote: >>> On Friday 23 September 2011 18:28:41 Felix Frank wrote: >>>> On 09/23/2011 06:18 PM, Bart Coninckx wrote: >>>>> Felix, >>>>> do you combine your setup with clustering software? Or do you script a >>>>> live migration? I'm intrigued by how you handle the timing in the >>>>> latter case. >>>> >>>> ah, I didn't make this really clear. >>>> >>>> I haven't set this up with either live migration capabilities nor >>>> pacemaker. All I have is a hot standby for manual recovery in case of a >>>> primary node failure. Sorry. >>>> >>>> I believe that for pacemaker, you would have both your nodes be primary >>>> at all times (i.e., not use a master-slave set at all). >>>> Not a thrilling perspective, I guess. >>> >>> Dual primary isn't really needed (but its very nice to have). >>> If you use one drbd-resource per vm, you need the dual-primary only >>> during the migration. >>> You can also run single-master that is exported via iscsi/aoe and mounted >>> to all nodes, cluster filesystem on top and you also get an extendible >>> vm- platform. But then you will have vms writing over network to the >>> other node through iscsi which is writing back to your node via drbd... >> >> That is an interesting idea, though it brakes a bit the high >> availability mission: if one node goes down, you would need to connect >> to the same node (local iSCSI session). I'm told this is not good. It >> would be an ideal situation though, except for the additional network >> cards (seperation iSCSI and DRBD traffic). > > True, local iscsi is not nice. But you can get around this by booting your > machines from an gpxe-iso/floppy and tell them the iscsi-device via dhcp. you mean the virtual machines I suppose. that's actually not a bad idea. thank you! >That > is actually a pretty cool solution, it scales to more then two nodes rather > easily. And when you decide that a vm needs to many resources, you can always > adopt the mac-addresses in your dhcp-config and boot that iscsi-image on a real > machine. The "problem" with this solution is that it has that double-network- > traffic penalty when a vm runs on the drbd-slave, it will send both read- and > write-requests across the network two times and you loose the advantage of > drbds local reading. But when your system get big enough, you will probably > not run the vm's on the drbd machines to optimize performance... I suppose this can be partially helped by dedicating network cards for iSCSI and DRBD > Have a nice weekend, U2, Arnold, b. > Arnold > > > > _______________________________________________ > drbd-user mailing list > drbd-user at lists.linbit.com > http://lists.linbit.com/mailman/listinfo/drbd-user