git.net

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Deprecating/removing PropertyFileSnitch?


Say you restarted all instances in the cluster and status for some host goes missing. Now when you start a host replacement, the new host won’t learn about the host whose status is missing and the view of this host will be wrong.

PS: I will be happy to be proved wrong as I can also start using Gossip snitch :) 

> On Oct 19, 2018, at 2:41 PM, Jeremy Hanna <jeremy.hanna1234@xxxxxxxxx> wrote:
> 
> Do you mean to say that during host replacement there may be a time when the old->new host isn’t fully propagated and therefore wouldn’t yet be in all system tables?
> 
>> On Oct 17, 2018, at 4:20 PM, sankalp kohli <kohlisankalp@xxxxxxxxx> wrote:
>> 
>> This is not the case during host replacement correct?
>> 
>> On Tue, Oct 16, 2018 at 10:04 AM Jeremiah D Jordan <
>> jeremiah.jordan@xxxxxxxxx> wrote:
>> 
>>> As long as we are correctly storing such things in the system tables and
>>> reading them out of the system tables when we do not have the information
>>> from gossip yet, it should not be a problem. (As far as I know GPFS does
>>> this, but I have not done extensive code diving or testing to make sure all
>>> edge cases are covered there)
>>> 
>>> -Jeremiah
>>> 
>>>> On Oct 16, 2018, at 11:56 AM, sankalp kohli <kohlisankalp@xxxxxxxxx>
>>> wrote:
>>>> 
>>>> Will GossipingPropertyFileSnitch not be vulnerable to Gossip bugs where
>>> we
>>>> lose hostId or some other fields when we restart C* for large
>>>> clusters(~1000 instances)?
>>>> 
>>>>> On Tue, Oct 16, 2018 at 7:59 AM Jeff Jirsa <jjirsa@xxxxxxxxx> wrote:
>>>>> 
>>>>> We should, but the 4.0 features that log/reject verbs to invalid
>>> replicas
>>>>> solves a lot of the concerns here
>>>>> 
>>>>> --
>>>>> Jeff Jirsa
>>>>> 
>>>>> 
>>>>>> On Oct 16, 2018, at 4:10 PM, Jeremy Hanna <jeremy.hanna1234@xxxxxxxxx>
>>>>> wrote:
>>>>>> 
>>>>>> We have had PropertyFileSnitch for a long time even though
>>>>> GossipingPropertyFileSnitch is effectively a superset of what it offers
>>> and
>>>>> is much less error prone.  There are some unexpected behaviors when
>>> things
>>>>> aren’t configured correctly with PFS.  For example, if you replace
>>> nodes in
>>>>> one DC and add those nodes to that DCs property files and not the other
>>> DCs
>>>>> property files - the resulting problems aren’t very straightforward to
>>>>> troubleshoot.
>>>>>> 
>>>>>> We could try to improve the resilience and fail fast error checking and
>>>>> error reporting of PFS, but honestly, why wouldn’t we deprecate and
>>> remove
>>>>> PropertyFileSnitch?  Are there reasons why GPFS wouldn’t be sufficient
>>> to
>>>>> replace it?
>>>>>> ---------------------------------------------------------------------
>>>>>> To unsubscribe, e-mail: dev-unsubscribe@xxxxxxxxxxxxxxxxxxxx
>>>>>> For additional commands, e-mail: dev-help@xxxxxxxxxxxxxxxxxxxx
>>>>>> 
>>>>> 
>>>>> ---------------------------------------------------------------------
>>>>> To unsubscribe, e-mail: dev-unsubscribe@xxxxxxxxxxxxxxxxxxxx
>>>>> For additional commands, e-mail: dev-help@xxxxxxxxxxxxxxxxxxxx
>>>>> 
>>>>> 
>>> 
>>> 
>>> ---------------------------------------------------------------------
>>> To unsubscribe, e-mail: dev-unsubscribe@xxxxxxxxxxxxxxxxxxxx
>>> For additional commands, e-mail: dev-help@xxxxxxxxxxxxxxxxxxxx
>>> 
>>> 
> 
> 
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: dev-unsubscribe@xxxxxxxxxxxxxxxxxxxx
> For additional commands, e-mail: dev-help@xxxxxxxxxxxxxxxxxxxx
> 

---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@xxxxxxxxxxxxxxxxxxxx
For additional commands, e-mail: dev-help@xxxxxxxxxxxxxxxxxxxx