Tired of checking iotop and seeing that your drbd partition is using 99.99% of io all the time and finding your drbd device performs slow in general?
This is especially an issue in versions of DRBD in the 8.3 tree in particular one documented case is on "8.3.13" but it likely applies to other devices.
The symptoms are that resyncing is fine and normal but any reasonable amount of activity is very slow and lagged and creates a high server load and con........
This is what fixed it:
[root@box13 ~]# dd if=/dev/zero of=/dev/md160 bs=512 count=500
Basically you need to wipe out more than just the 512 byte partition table so 512 bytes * 500 is more than enough to make DRBD happy and think the partition is now empty.
The reason this happens is because it gets confused when there is a previous partition with data on the device you are using.
root@box13 ~]# d........
This assumes that you've at least created the correct partition for your DRBD already.
Notice that I am "diskless", that's because either your DRBD partition doesn't exist/has been renamed (eg. sdb becomes sda when sdb dies and you reboot) or because that drive is really actually dead/gone.
*If you need to permanently change the partition/device for your resource be sure to edit /etc/drbd.conf on both hosts and reload the config.
(replace r0 with........