Hi, as far as I understand a 3 node steup with dual primary and 3rd node
for disaster recovery is not possible:
http://www.gossamer-threads.com/lists/drbd/users/22188#22188
So I tried the following setup as suggested by Lars:
drbd-1: 192.168.3.111 (first node)
drbd-2: 192.168.3.112 (second node)
drbd-dr: 192.168.3.113 (disaster recovery node)
drbd-1 and drbd-2 should be Primary/Primary (I need it as a backing
store for kvm VMs)
drbd-2 replicates with drbd-dr in Primary/Secondary mode and protocol A
drbd-2 replicates resource stacked on the previous one with drbd-1 and
protocol C
Scheme:
drbd1 <---C---> drbd1
drbd0 ---A----> drbd0
node-drbd-1 node-drbd-2 node-drbd-dr
The resources start up and sync. The i tried the following:
format drbd1 device on drbd-1
mount drbd1 device on drbd-1
create test file drbd-1-test
umount drbd1 device on drbd-1
mount drbd1 device on drbd-2
create test file drbd-2-test
I can see both drbd-1-test and drbd-2-test
umount drbd1 device on drbd-2
demote and stop stacked drbd1 resource on drbd-1 and drbd-2
promote drbd0 resource on drbd-dr
mount drbd0 device on drbd-dr
create test file drbd-dr-test
I can see drbd-1-test drbd-2-test drbd-dr-test
demote drbd0 resource on drbd-dr
start and promote drbd1 resource on drbd-1 and drbd-2
mount drbd1 on drbd-2
I can see drbd-1-test drbd-2-test drbd-dr-test
umount drbd1 on drbd-2
mount drbd1 on drbd-1
I can see drbd-1-test drbd-2-test ONLY!!
If I invalidate the resource on drbd-1 and do a full resync the 3rd file
appear.
Config follows:
resource drbd-dr {
protocol C;
startup {
become-primary-on drbd-2.apra.it;
}
on drbd-2.apra.it {
device /dev/drbd0;
disk /dev/vdb;
address 192.168.3.112:7788;
meta-disk internal;
}
on drbd-dr.apra.it {
device /dev/drbd0;
disk /dev/vdb;
address 192.168.3.113:7788;
meta-disk internal;
}
}
resource drbd {
startup {
become-primary-on both;
}
net {
allow-two-primaries;
}
protocol C;
stacked-on-top-of drbd-dr {
device /dev/drbd1;
address 192.168.3.112:7789;
}
on drbd-1.apra.it {
device /dev/drbd1;
disk /dev/vdb;
address 192.168.3.111:7789; # Public IP of the backup node
meta-disk internal;
}
}
--
Cristian Mammoli
APRA SISTEMI srl
Via Brodolini,6 Jesi (AN)
tel dir. +390731719822
Web www.apra.it
e-mail [email protected]
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