Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
Thanks for the reply Felix,
Log extracts are included below & attached as requested.
> Hi,
>
> On 01/24/2011 01:20 AM, Lew wrote:
> > I've encountered some unexpected behavior with a split brain
> > instance.
> > It seems from what has occurred that the default behavior is set to
> > roll
> > back & discard changes.
> >
> > Recently in my sand pit, I've been manually disconnecting resources
> > as a
> > an ad hock way of maintaining a snapshot for roll back.
> > This way if I'm happy with changes, I can reconnect and within
> > seconds
> > we're fully synced again.
> >
> > I moved a server yesterday and discovered after a drbdadm connect
> > all,
> > that one of the resources had split brained and discarded a few days
> > worth of work;
> > rolling back to the point in time when the resource was first
> > disconnected.
> >
> > What's interesting to me is that the disconnected secondary node had
> > never been set primary, so how did we end up in split brain?
> > I also do not understand why it was only this resource that split
> > brained, when others that existed in seemingly identical
> > configurations
> > and states did not.
> >
> > I expect I'll need to explicitly prohibit this behavior in a global
> > net
> > section covering after-sb-0pri etc;
> > I still don't understand why discard & roll back has been chosen
> > default
> > behavior, I'm contending from my experience it should not be.
>
> It's not.
OK, seems to me something smells then.
> > Looks to me like a few days work is lost, but if anyone knows of a
> > way
> > to recover from a roll back discard scenario, I'd be very happy to
> > find out.
>
> Please share pertinent logs and drbd configuration.
Config
------
resource x2 {
protocol A;
syncer {
rate 100M;
}
on emlsurit-v4 {
device /dev/drbd9;
disk /dev/r50lvm/emlsurit-x2-drbd;
address 192.168.254.100:7799;
flexible-meta-disk internal;
}
on emlsurit-v5 {
device /dev/drbd9;
disk /dev/r50lvm/emlsurit-x2-drbd;
address 192.168.254.101:7799;
meta-disk internal;
}
}
Global Config (comments removed)
-------------
global {
usage-count yes;
}
common {
protocol A;
handlers {
pri-on-incon-degr "/usr/lib/drbd/notify-pri-on-incon-degr.sh";
pri-lost-after-sb "/usr/lib/drbd/notify-pri-lost-after-sb.sh";
echo o > /proc/sysrq-trigger ; halt -f";
local-io-error "/usr/lib/drbd/notify-io-error.sh";
split-brain "/usr/lib/drbd/notify-split-brain.sh root";
out-of-sync "/usr/lib/drbd/notify-out-of-sync.sh root";
}
startup {
}
disk {
no-disk-flushes;
no-md-flushes;
}
net {
}
syncer {
}
}
Message Log extract (A bit long to post)-- see attached.
Cheers & thanks,
Lew
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