Thank you for the advices! Best!
Sergio On Thu, Feb 13, 2020, 7:44 PM Erick Ramirez <erick.rami...@datastax.com> wrote: > Option 1 is a cheaper option because the cluster doesn't need to rebalance > (with the loss of a replica) post-decommission then rebalance again when > you add a new node. > > The hints directory on EBS is irrelevant because it would only contain > mutations to replay to down replicas if the node was a coordinator. In the > scenario where the node itself goes down, other nodes will be storing hints > for this down node. The saved_caches are also useless if you're > bootstrapping the node into the cluster because the cache entries are only > valid for the previous data files, not the newly streamed files from the > bootstrap. Similarly, your commitlog directory will be empty -- that's > the whole point of running nodetool drain. :) > > A little off-topic but *personally* I would co-locate the commitlog on > the same 950GB NVMe SSD as the data files. You would get a much better > write performance from the nodes compared to EBS and they shouldn't hurt > your reads since the NVMe disks have very high IOPS. I think they can > sustain 400K+ IOPS (don't quote me). I'm sure others will comment if they > have a different experience. And of course, YMMV. Cheers! > > > > On Fri, 14 Feb 2020 at 14:16, Sergio <lapostadiser...@gmail.com> wrote: > >> We have i3xlarge instances with data directory in the XFS filesystem that >> is ephemeral and *hints*, *commit_log* and *saved_caches* in the EBS >> volume. >> Whenever AWS is going to retire the instance due to degraded hardware >> performance is it better: >> >> Option 1) >> - Nodetool drain >> - Stop cassandra >> - Restart the machine from aws-cli to be restored in a different VM >> from the hypervisor >> - Start Cassandra with -Dcassandra.replace_address >> - We lose only the ephemeral but the commit_logs, hints, saved_cache >> will be there >> >> >> OR >> >> Option 2) >> - Add a new node and wait for the NORMAL status >> - Decommission the one that is going to be retired >> - Run cleanup with cstar across the datacenters >> >> ? >> >> Thanks, >> >> Sergio >> >
