Expansion probably much faster in 4.0 with complete sstable streaming (skips ser/deser), though that may have diminishing returns with vnodes unless you're using LCS.
Dynamo on demand / autoscaling isn't magic - they're overprovisioning to give you the burst, then expanding on demand. That overprovisioning comes with a cost. Unless you're actively and regularly scaling, you're probably going to pay more for it. It'd be cool if someone focused on this - I think the faster streaming goes a long way. The way vnodes work today make it difficult to add more than one at a time without violating consistency, and thats unlikely to change, but if each individual node is much faster, that may mask it a bit. On Mon, Dec 9, 2019 at 12:35 PM Carl Mueller <carl.muel...@smartthings.com.invalid> wrote: > Dynamo salespeople have been pushing autoscaling abilities that have been > one of the key temptations to our management to switch off of cassandra. > > Has anyone done any numbers on how well dynamo will autoscale demand > spikes, and how we could architect cassandra to compete with such abilities? > > We probably could overprovision and with the presumably higher cost of > dynamo beat it, although the sales engineers claim they are closing the > cost factor too. We could vertically scale to some degree, but node > expansion seems close. > > VNode expansion is still limited to one at a time? > > We use VNodes so we can't do netflix's cluster doubling, correct? With > cass 4.0's alleged segregation of the data by token we could though and > possibly also "prep" the node by having the necessary sstables already > present ahead of time? > > There's always "caching" too, but there isn't a lot of data on general > fronting of cassandra with caches, and the row cache continues to be mostly > useless? >
