ctl_isc_lun_sync: Received conflicting HA LUN

[Mikhail Zakharov]

Ah, and unfortunately CTL HA is two-node cluster, as I remember, there is no possibility to add the third one. So the third node is an external arbiter in that case.


> 24 апр. 2018 г., в 14:04, Karli Sjöberg <karli at inparadise.se> написал(а):
> 
>> On Tue, 2018-04-24 at 13:00 +0200, Karli Sjöberg via freebsd-fs wrote:
>>> On Tue, 2018-04-24 at 12:32 +0300, Mikhail Zakharov wrote:
>>> Hi Karli,
>>> 
>>> Thank you, I’m just exploring the storage abilities of my preferred
>>> OS - FreeBSD. 
>>> 
>>> Three nodes are preferable to choose the quorum for sure, but my
>>> idea
>>> was not to establish contacts between nodes. Instead of it, BQ uses
>>> a
>>> small partition for the “quorum” on the same space where data
>>> volume
>>> is located. 
>> 
>> Yes, of course. But there´s nothing you from having three nodes
> 
> 's/nothing you/nothing stopping you/'
> 
>> connected to the same partition and being able to make more accurate
>> choices on when to take over?
>> 
>> If one node stops updating stamps, take over. If two nodes stops
>> updating, then the problem is likely network-related and _must not_
>> take over to avoid split brain. Something like that?
>> 
>> /K
>> 
>>> And if a node looses access to the quorum it means, it looses
>>> access
>>> to the data volume too. Now, BQ runs on both nodes and both BQ
>>> instances write stamps to the quorum partition. If for any reason
>>> BQ
>>> on one node detects, the other node stops updating it’s stamps, it
>>> performs failover procedure. It’s quite a questionable, rude way, I
>>> can agree, and that’s why I always write a warning to use the BeaST
>>> for testing only purposes. 
>>> 
>>> Best regards,
>>> Mike
>>> 
>>>> 24 апр. 2018 г., в 9:09, Karli Sjöberg <karli at inparadise.se>
>>>> написал(а):
>>>> 
>>>>>> On Mon, 2018-04-23 at 13:11 -0400, Mike Tancsa wrote:
>>>>>> On 4/23/2018 12:59 PM, Mikhail Zakharov wrote:
>>>>>> 
>>>>>> Hello Mike,
>>>>>> 
>>>>>> Thank you for your interest to my paper. I appreciate it very
>>>>>> much!
>>>>>> Your error may be a consequence of the initial HA
>>>>>> misconfiguration.
>>>>>> What is in your /boot/loader.conf? Although the described
>>>>>> config is
>>>>>> quite simple, I can recheck the instruction in my paper in a
>>>>>> couple
>>>>>> of weeks only, unfortunately I’m on vacation right now.
>>>> 
>>>> [snip]
>>>> 
>>>> I read your articles on CTL HA, BQ and BeaST, and just wanted to
>>>> say
>>>> they are amazing, good job!
>>>> 
>>>> One thing I´m wondering about though is if you can claim HA with
>>>> just
>>>> two nodes, usually you need at least three, where the third is a
>>>> tie-
>>>> breaker. Otherwise with your current setup, both systems may
>>>> loose
>>>> contact with each other while both still being powered on,
>>>> leading
>>>> to
>>>> potential split brain situations. What are your thoughts about
>>>> that?
>>>> 
>>>> /K