Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On 07/07/16 11:14 PM, Klint Gore wrote: > *From:*drbd-user-bounces at lists.linbit.com > [mailto:drbd-user-bounces at lists.linbit.com] *On Behalf Of *James Ault > *Sent:* Friday, 8 July 2016 2:02 AM > *To:* James Ault; drbd-user at lists.linbit.com > *Subject:* Re: [DRBD-user] DRBD Recovery actions without Pacemaker > > > > I see the Manual Failover section of the DRBD 8.4.x manual, and I see > that it requires that the file system be umounted before attempting to > promote and mount the file system on the secondary. > > What I meant by "those status flags" in my first message is that when a > node mounts a file system, that file system is marked as mounted > somewhere on that device. The "mounted" status flag is what I'm trying > to describe, and I'm not sure if I have the correct name for it. > > Does pacemaker or manual failover handle the case where a file server > experiences a hard failure where the umount operation is impossible? > How can the secondary copy of the file system be mounted if the umount > operation never occurred and cannot occur on server1? > > > > The basic manual failover described in the manual is when you choose > manually switch over to the other machine. You would use that if you > wanted to do maintenance on the primary. > > If the primary dies by itself, you don’t need to unmount it - that’s > where fencing comes into play. You need to make sure that the “dead” > node is well and truly dead and going to stay that way. "and going to stay that way." A bit of nuance; It's perfectly fine for the fenced node to reboot, and that is the most common configuration. All that really matters from a fence/stonith action's perspective is that the node was "off". When it boots back up (assuming it can), the software (pacemaker, drbd, etc) is in a "clean" state. It will not try to do anything related to the cluster until it rejoins. > What you’re trying to achieve is the same as what my setup is. On both > servers, nothing starts at boot and only the root file system mounts > from fstab. A script is run to make one of them primary, mount the file > systems of the drbd devices, add the external ip, start the network > services. The other node just becomes drbd secondary and that’s it. At > failover, the dead machine is pulled from the rack and taken away, then > the secondary becomes primary, mounts the file systems of the drbd > devices, adds the external ip, starts the network services. If I’m > doing manual failover for maintenance, then on the primary, the network > services are stopped, the external ip address is removed, the file > systems are unmounted, drbd is demoted to secondary. The other machine > is promoted just like hardware failover. > > Klint. -- Digimer Papers and Projects: https://alteeve.ca/w/ What if the cure for cancer is trapped in the mind of a person without access to education?