>There's a system property (actually 2)Which ones?
On Wednesday, April 19, 2017 9:17 AM, Jeff Jirsa <jji...@apache.org> wrote:
On 2017-04-12 11:30 (-0700), Vlad <qa23d-...@yahoo.com> wrote:
> Interesting, there is no such explicit warning for v.3
> https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsAddNodeToCluster.html
> It says
> - Start the bootstrap node.
> - verify that the node is fully bootstrapped and all other nodes are up
>(UN)
>
> Does it mean that we should start them one by one? May somebody from
> developers can clarify this issue?
You should treat range movements (bootstrap/decom/etc) in 3.0 the same way you
treated 2.0/2.1/2.2 - there's nothing special (as far as I know) to make it any
more safe than 2.x was.
The warnings and restrictions are because simultaneous range movements PROBABLY
violate your assumed consistency guarantees if you're using vnodes. If you're
using single token, this can be avoided.
If you really know what you're doing, you can tell cassandra to let you do
simultaneous range movements anyway. There's a system property (actually 2)
that will let you tell cassandra you know the tradeoffs, and then you can
bootstrap/decom/etc more than one node at a time. Generally, it's one of those
things where if you have to ask about it, you probably should just stick to the
default one-at-a-time guidelines (which isn't meant to sound condescending, but
it's an area where you can definitely violate consistency and maybe even lose
data if you're not sure).
- Jeff
