Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 05/21/2012 11:41 AM, Arnold Krille wrote: > On Monday 21 May 2012 14:06:22 Florian Haas wrote: >> You've already stated that you're able to separate file access per >> node. And you only want access from two nodes, otherwise you wouldn't >> be considering DRBD. So, that makes your system a textbook use case >> for two separate single-Primary DRBD resources. This type of setup is >> orders of magnitude simpler to get right than a dual-Primary >> configuration, as both Arnold and Madison (digimer) have pointed out >> earlier. It completely sidesteps the issue of managing a cluster >> filesystem, and if you're concerned about being able to grow your >> filesystem later, just slap your DRBD resources onto LVM logical >> volumes, and you can resize at will (to the extent that your >> filesystem supports it). > The only down-side of "one single-primary-drbd per vm" is that you 'loose' > live-migration compared to dual-primary or a cluster fs like gluster, moosefs, > ceph or sheepdog. With DRBD 8.4 you can switch a resource to dual primary temporarily on the fly, allowing for live migration. Unfortunately this isn't automated in Pacemaker yet so there is still some manual intervention that needs to take place. The good news though, is that there's a new feature in DRBD "coming soon" that will enable this functionality without any modifications to Pacemaker/the OCFs. This of course applies in a situation where you're using the raw DRBD device as a backing device for each VM. Brian -- : Brian Hellman : LINBIT | "Your Way to High Availability" : 1-503-573-1262 | 1-877-4-LINBIT : Web: http://www.linbit.com : : Twitter: http://www.linbit.com/en/twitter : Facebook: http://www.linbit.com/en/facebook