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Re: Deprecating/removing PropertyFileSnitch?


On Mon, Oct 22, 2018 at 7:09 PM J. D. Jordan <jeremiah.jordan@xxxxxxxxx>
wrote:

> Do you have a specific gossip bug that you have seen recently which caused
> a problem that would make this happen?  Do you have a specific JIRA in mind?


Sankalp linked a few others, but also
https://issues.apache.org/jira/browse/CASSANDRA-13700


>   “We can’t remove this because what if there is a bug” doesn’t seem like
> a good enough reason to me. If that was a reason we would never make any
> changes to anything.
>

How about "we know that certain fields that are gossiped go missing even
after all of the known races are fixed, so removing an existing
low-maintenance feature and forcing users to rely on gossip for topology
may be worth some discussion".


> I think many people have seen PFS actually cause real problems, where with
> GPFS the issue being talked about is predicated on some theoretical gossip
> bug happening.
>

How many of those were actually caused by incorrect fallback from GPFS to
PFS, rather than PFS itself?


> In the past year at DataStax we have done a lot of testing on 3.0 and 3.11
> around adding nodes, adding DC’s, replacing nodes, replacing racks, and
> replacing DC’s, all while using GPFS, and as far as I know we have not seen
> any “lost” rack/DC information during such testing.
>

I've also run very large GPFS clusters in the past without much gossip
pain, and I'm in the "we should deprecate PFS" camp, but it is also true
that PFS is low maintenance and mostly works. Perhaps the first step is
breaking the GPFS->PFS fallback that people don't know about, maybe that'll
help?