Testing Data Replication/Synchronize on DRBD

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After configuration DRBD in the previous article, we must test first for ensure whether DRBD has been working properly or not. This is some testing to ensure DRBD has been worked

# TESTING ON NODE1

– Create folder tmp in /mnt folder

mkdir /mnt/tmp

– Mount DRBD devices into tmp folder who has been created

mount /dev/drbd0 /mnt/tmp

– Create file/folder into tmp folder

touch /mnt/tmp/created-on-node1.txt

– Please check whether file created-on-node1.txt has been there

ls /mnt/tmp/

– For testing/check on node2, umount DRBD devices and demoting into secondary

umount /dev/drbd0
drbdadm secondary r0

– Make sure DRBD has been demoted into Secondary

service drbd status

# TESTING ON NODE2

– Create folder tmp in /mnt folder

mkdir /mnt/tmp

– Promoting DRBD into Primary

drbdadm primary r0

– Mount DRBD devices into tmp folder who has been created

mount /dev/drbd0 /mnt/tmp

– Please check whether file created-on-node1.txt has been there too

ls /mnt/tmp/

If the file has been there, it’s meant DRBD has been replicated

– Umount DRBD devices, demoting again into secondary and promoting node1 into primary

umount /dev/drbd0
drbdadm secondary r0
service drbd status

# PROMOTING NODE1 INTO PRIMARY

run the following command on node1

service drbd status
drbdadm primary r0

Good luck and hopefully useful 😀

8 comments

  1. I’ve following your work sr, its unfourtunately you dont work under centos 7 but well. Its a great help for me since im working with zimbra now.
    Thanks a lot!

  2. Hi Iman,

    I’ve followed your instruction and it is working as you described.
    But actually I don’t understand how come it is considered as working?

    By data replication, I thought each node would have its /dev/drbd0 to be mounted all the time and every changes made on whatever nodes to be reflected on the other node as well.
    I still don’t get why we need to do promote/demote on each side.

    Maybe I have a wrong concept about drbd. It would be very kind if you could enlighten me

    1. Hi,
      You can sync any folder/file on DRBD devices if DRBD has mounted. DRBD can be mounted if have primary status. You can’t mount DRBD on secondary. Albeit secondary did not mounted, secondary always syncing with primary

  3. Dear Iman
    I have successfully deployed drbd9 + zimbra in ubuntu 20.04. Everything goes fine. I am facing one thing, when node-1 goes down, node -2 getting up but zimbra all service not getting ok, I have to restart zimbra service manually or by script that’s why down time(zimbra web) getting more.

    Is it normal or I have done any mistake..? If have any solution please give me.(I mean no need to restart zimbra service when server switch)
    use:
    ubuntu 20.04, zimbra 8.8.15, drbd9, pacemaker, corosync and pcs

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