[Drbd-dev] About the UUID

home_king home_king at 163.com
Wed Dec 20 08:06:57 CET 2006

hi, Philipp.

Now drbd-0.8.x uses UUID instead of GC as the data-relationship-detection
-tool, right? Its logic seems clearer than GC. However, I am confused
about the UUID in the two-primaries-healedpartition scenario.

Given the original uuids below (both nodes are connected):
P <5,0,0,0>      S <5,0,0,0>
then, I plug out the wire of the primary node (disconnected):
P <6,5,0,0>      S <5,0,0,0>
I let the downgraded secondary become new primary, UUID should become:
P <6,5,0,0>      S <6,5,0,0>
Finally, I recover the wire of primary. And Now, there comes my problem.
Accordding to the UUID algorithm, when Cs == Cp, no resynchronisation
necessary. However it is obviously split-brain, and drbd ignores it.


BTW, I did not test such scenario, because I can't compile drbd-0.8.x
in my RedHat AS4 distro. I just browsed the doc & code. :-)


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