Ariel, having it in C* process makes sense to me. Please correct me if I'm wrong here, but shouldn't using ZCS to transfer have no distinguishable difference in overhead from doing it using the sidecar? Since the underlying call is sendfile, never hitting userspace, I can't see why we'd opt for the transfer in sidecar. What's the advantage of duplicating the work that's already been done?
I can see using the sidecar for coordination to start and stop instances or do things that require something out of process. Jon On Thu, Apr 18, 2024 at 12:44 PM Ariel Weisberg <ar...@weisberg.ws> wrote: > Hi, > > If there is a faster/better way to replace a node why not have Cassandra > support that natively without the sidecar so people who aren’t running the > sidecar can benefit? > > Copying files over a network shouldn’t be slow in C* and it would also > already have all the connectivity issues solved. > > Regards, > Ariel > > On Fri, Apr 5, 2024, at 6:46 AM, Venkata Hari Krishna Nukala wrote: > > Hi all, > > I have filed CEP-40 [1] for live migrating Cassandra instances using the > Cassandra Sidecar. > > When someone needs to move all or a portion of the Cassandra nodes > belonging to a cluster to different hosts, the traditional approach of > Cassandra node replacement can be time-consuming due to repairs and the > bootstrapping of new nodes. Depending on the volume of the storage service > load, replacements (repair + bootstrap) may take anywhere from a few hours > to days. > > Proposing a Sidecar based solution to address these challenges. This > solution proposes transferring data from the old host (source) to the new > host (destination) and then bringing up the Cassandra process at the > destination, to enable fast instance migration. This approach would help to > minimise node downtime, as it is based on a Sidecar solution for data > transfer and avoids repairs and bootstrap. > > Looking forward to the discussions. > > [1] > https://cwiki.apache.org/confluence/display/CASSANDRA/CEP-40%3A+Data+Transfer+Using+Cassandra+Sidecar+for+Live+Migrating+Instances > > Thanks! > Hari > > >
