RAFT and CTDB
steve at steve-ss.com
Mon Dec 8 04:11:03 MST 2014
On 08/12/14 06:26, Martin Schwenke wrote:
> On Sat, 6 Dec 2014 15:55:28 +1100, Martin Schwenke <martin at meltin.net>
>> As various people have mentioned, the default filesystem requirement
>> is fcntl(2) locking support to support the CTDB recovery lock.
>> There's an assumption that if the ping_pong test succeeds then CTDB's
>> recovery lock will work. If that's not true then we need to create a
>> new test. However, I don't believe anyone has conclusively shown
>> ping_pong not to be a reliable test.
> I rushed through some of this late on Saturday night and was actually
> fooled. I thought the ping_pong test had passed and then CTDB failed
> in the same way that some people have described on this mailing list.
> I have since updated the ping_pong wiki page at:
> by adding some bold and an extra section.
> The summary is that you can't race through and simply confirm that the
> test prints the correct data_increment value when running with -rw.
> For the recovery lock to work you need to run the non -rw version and
> actually confirm that *the locking rate drops dramatically*. If it
> doesn't then it is *not* working!
> peace & happiness,
The OP has confirmed that the test works but the lock doesn't.
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