RAFT and CTDB

Martin Schwenke martin at meltin.net
Mon Dec 8 04:39:40 MST 2014


On 8 December 2014 10:11:03 PM AEDT, steve <steve at steve-ss.com> wrote:
>On 08/12/14 06:26, Martin Schwenke wrote:
>> On Sat, 6 Dec 2014 15:55:28 +1100, Martin Schwenke
><martin at meltin.net>
>> wrote:
>>
>>> 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:
>>
>>    https://wiki.samba.org/index.php/Ping_pong
>>
>> 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!

>Thanks.
>The OP has confirmed that the test works but the lock doesn't.

Can the OP please describe the steps they took to run the test and the output they saw at each stage?

Thanks...

peace & happiness,
martin



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