Thanks a lot, Jordan, Jeff, Abe, guo and Jon! This is really helpful. On Wed, Oct 9, 2024 at 8:59 AM Jon Haddad <j...@rustyrazorblade.com> wrote:
> I've worked with a few hundred teams now, including the major ones that > used single token (Apple, Netflix, Spotify), and pretty much all the rest > used some form of vnodes. > > Jeff did a good job of summarizing the tradeoffs and I don't have anything > to add. > > I would never, ever, recommend > 4 tokens. There's just not a practical > reason to do it. I've heard claims of people wanting elastic clusters... > can't recall too many times where I've needed to shrink Cassandra. It's a > really weird thing to keep in your back pocket when it makes daily > operations so much worse. Even in that case, you can remove, then add. > It's not great, but you might do it like once over multiple years. So I > always say don't go over 4 because the tradeoff isn't practical. > > Jon > > > > > On Tue, Oct 8, 2024 at 10:58 PM Jeff Jirsa <jji...@gmail.com> wrote: > >> You don’t have to double. >> >> You can add 1 node at a time - you just have to move every other token to >> stay balanced >> >> Most people don’t write the tooling to do that, but it’s not that >> complicated >> >> Calculate the token positions with N nodes >> Calculate the token positions with N+1 nodes >> >> Bootstrap the new machine at whichever N+1 token is furthest from an >> existing token >> For each existing node: >> Run cleanup >> Move node to the new token >> >> Run cleanup again >> >> It’s involved but straight forward, online, and safe. >> >> Because there’s only one token per node you can bootstrap/move in batches >> (offset by 2x RF - so if you have 100 machines and RF=3, you can have 16 >> machines bootstrapping or moving at the same time). You can’t do that >> safely with vnodes. >> >> >> On Oct 9, 2024, at 12:51 AM, guo Maxwell <cclive1...@gmail.com> wrote: >> >> >> I think cost is a very important point if you are going to use *single** >> token i*f your cluster will be very large , because every time the >> cluster is expanded, the nodes need to be doubled.100 -> 200, 200->400 ... >> This is one of the reasons why we maintain many small clusters. >> >> of course its availability will be better . >> >> Abe Ratnofsky <a...@aber.io> 于2024年10月9日周三 11:56写道： >> >>> Here’s the best post I’m aware of: >>> https://jolynch.github.io/pdf/cassandra-availability-virtual.pdf >>> >>> On Oct 7, 2024, at 17:30, Long Pan <panlong...@gmail.com> wrote: >>> >>> >>> >>> Hi Cassandra Community, >>> >>> I’m currently exploring the use of *single vnode* (single token) per >>> node in large-scale Cassandra deployments. I've come across discussions >>> suggesting that some heavy users like Apple and Netflix have opted for this >>> configuration to simplify operations and achieve more predictable >>> performance. >>> >>> I’d like to ask if anyone could point me to *resources* (blog posts, >>> conference talks, case studies or even personal experiences) that dive >>> deeper into: >>> >>> - The *rationale* behind using a single vnode instead of multiple >>> vnodes. >>> - The *operational benefits* and any potential trade-offs >>> encountered. >>> >>> Thank you in advance for your insights and any pointers you can provide! >>> >>> Best regards, >>> Long >>> >>>
