Usynced blocks if replication is interrupted during initial sync

[Joel Colledge]

> We are still seeing the issue as described but perhaps I am not putting the invalidate
> at the right spot
>
> Note - I've added it at step 6 below, but I'm wondering if it should be after
> the additional node is configured and adjusted (in which case I would need to
> unmount as apparently you can't invalidate a disk in use)
>
> So do I need to invalidate after every node is added?

With my reproducer, the workaround at step 6 works.

> Also Note, the node-id in the logs from the kernel is 0 but peers are configured with 1 and 2 ,
> is this an issue or they separate ids?

I presume you are referring to the line:
"Copying bitmap of peer node_id=0"
The reason that node ID 0 appears here is that DRBD stores a bitmap of
the blocks that have changed since it was first brought up. This is
the "day0" bitmap. This is stored in all unused bitmap slots. All
unused node IDs point to one of these bitmaps. In this case, node ID 0
is unused. So this line means that it is using the day0 bitmap here.
This is unexpected, as mentioned in my previous reply.

Joel