[DRBD-user] Not able to test Automatic split brain recovery policies

[Dan Barker]

You don't show the status of the nodes, but I imagine you have two primary nodes. There is no handler specified for two primary nodes. Did you have two primary, disconnected nodes?

It shouldn't be possible to create split brain without writing on both nodes.

Dan

From: drbd-user-bounces at lists.linbit.com [mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of Shailesh Vaidya
Sent: Wednesday, April 10, 2013 1:58 AM
To: drbd-user at lists.linbit.com
Subject: [DRBD-user] Not able to test Automatic split brain recovery policies

Hello,

I am using DRBD 8.3.8

I have configured Automatic split brain recovery policies as below in /etc/drbd.conf

net {
max-buffers     2048;
ko-count 4;
after-sb-0pri discard-zero-changes;
after-sb-1pri discard-secondary;
}

My both machines are Virtual machines so not connected actual back-to-back connection. To reproduce split-brain, I am using below procedure,

1.On Primary disable Ethernet card from 'Virtual Machine properties'
2.Wait to Secondery to start switch over and again enable Ethernet card on Primary

Log shows mw that split-brain is occurred , however its shows connection dropped.

Apr  9 10:30:15 drbd1 kernel: block drbd0: uuid_compare()=100 by rule 90
Apr  9 10:30:15 drbd1 kernel: block drbd0: helper command: /sbin/drbdadm initial-split-brain minor-0
Apr  9 10:30:15 drbd1 kernel: block drbd0: helper command: /sbin/drbdadm initial-split-brain minor-0 exit code 0 (0x0)
Apr  9 10:30:15 drbd1 kernel: block drbd0: Split-Brain detected but unresolved, dropping connection!
Apr  9 10:30:15 drbd1 kernel: block drbd0: helper command: /sbin/drbdadm split-brain minor-0
Apr  9 10:30:15 drbd1 kernel: block drbd0: helper command: /sbin/drbdadm split-brain minor-0 exit code 0 (0x0)
Apr  9 10:30:15 drbd1 kernel: block drbd0: conn( WFReportParams -> Disconnecting )

Full DRBD conf file

[root at drbd1 ~]# cat /etc/drbd.conf
global {
usage-count no;
}

resource r0 {
protocol C;
#incon-degr-cmd "echo !DRBD! pri on incon-degr | wall ; sleep 60 ; halt -f";

on drbd1 {
device     /dev/drbd0;
disk       /dev/sda3;
address    10.55.199.51:7789;
meta-disk  internal;
}
on drbd2 {
device    /dev/drbd0;
disk      /dev/sda3;
address   10.55.199.52:7789;
meta-disk internal;
}

disk {
on-io-error   detach;
}

net {
max-buffers     2048;
ko-count 4;
after-sb-0pri discard-zero-changes;
after-sb-1pri discard-secondary;
}

syncer {
rate 25M;
al-extents 257; # must be a prime number
}

startup {
wfc-timeout  20;
degr-wfc-timeout 120;    # 2 minutes.
}
}

[root at drbd1 ~]# vi /var/log/messages
[root at drbd1 ~]#
[root at drbd1 ~]# cat /etc/drbd.conf
global {
usage-count no;
}

resource r0 {
protocol C;
#incon-degr-cmd "echo !DRBD! pri on incon-degr | wall ; sleep 60 ; halt -f";

on drbd1 {
device     /dev/drbd0;
disk       /dev/sda3;
address    10.55.199.51:7789;
meta-disk  internal;
}
on drbd2 {
device    /dev/drbd0;
disk      /dev/sda3;
address   10.55.199.52:7789;
meta-disk internal;
}

disk {
on-io-error   detach;
}

net {
max-buffers     2048;
ko-count 4;
after-sb-0pri discard-zero-changes;
after-sb-1pri discard-secondary;
}

syncer {
rate 25M;
al-extents 257; # must be a prime number
}

startup {
wfc-timeout  20;
degr-wfc-timeout 120;    # 2 minutes.
}
}

[root at drbd1 ~]#


Is this configuration issue or my testing procedure is not proper?

Regards,
Shailesh Vaidya


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