Is there any update on this topic? It seems that things can make a big progress if Jake Luciani can find someone who can make the FileSystemProvider code accessible.
Jon Haddad <j...@jonhaddad.com> 于2023年12月16日周六 05:29写道： > At a high level I really like the idea of being able to better leverage > cheaper storage especially object stores like S3. > > One important thing though - I feel pretty strongly that there's a big, > deal breaking downside. Backups, disk failure policies, snapshots and > possibly repairs would get more complicated which haven't been particularly > great in the past, and of course there's the issue of failure recovery > being only partially possible if you're looking at a durable block store > paired with an ephemeral one with some of your data not replicated to the > cold side. That introduces a failure case that's unacceptable for most > teams, which results in needing to implement potentially 2 different backup > solutions. This is operationally complex with a lot of surface area for > headaches. I think a lot of teams would probably have an issue with the > big question mark around durability and I probably would avoid it myself. > > On the other hand, I'm +1 if we approach it something slightly differently > - where _all_ the data is located on the cold storage, with the local hot > storage used as a cache. This means we can use the cold directories for > the complete dataset, simplifying backups and node replacements. > > For a little background, we had a ticket several years ago where I pointed > out it was possible to do this *today* at the operating system level as > long as you're using block devices (vs an object store) and LVM [1]. For > example, this works well with GP3 EBS w/ low IOPS provisioning + local NVMe > to get a nice balance of great read performance without going nuts on the > cost for IOPS. I also wrote about this in a little more detail in my blog > [2]. There's also the new mount point tech in AWS which pretty much does > exactly what I've suggested above [3] that's probably worth evaluating just > to get a feel for it. > > I'm not insisting we require LVM or the AWS S3 fs, since that would rule > out other cloud providers, but I am pretty confident that the entire > dataset should reside in the "cold" side of things for the practical and > technical reasons I listed above. I don't think it massively changes the > proposal, and should simplify things for everyone. > > Jon > > [1] https://rustyrazorblade.com/post/2018/2018-04-24-intro-to-lvm/ > [2] https://issues.apache.org/jira/browse/CASSANDRA-8460 > [3] > https://aws.amazon.com/about-aws/whats-new/2023/03/mountpoint-amazon-s3/ > > > On Thu, Dec 14, 2023 at 1:56 AM Claude Warren <cla...@apache.org> wrote: > >> Is there still interest in this? Can we get some points down on >> electrons so that we all understand the issues? >> >> While it is fairly simple to redirect the read/write to something other >> than the local system for a single node this will not solve the problem for >> tiered storage. >> >> Tiered storage will require that on read/write the primary key be >> assessed and determine if the read/write should be redirected. My >> reasoning for this statement is that in a cluster with a replication factor >> greater than 1 the node will store data for the keys that would be >> allocated to it in a cluster with a replication factor = 1, as well as some >> keys from nodes earlier in the ring. >> >> Even if we can get the primary keys for all the data we want to write to >> "cold storage" to map to a single node a replication factor > 1 means that >> data will also be placed in "normal storage" on subsequent nodes. >> >> To overcome this, we have to explore ways to route data to different >> storage based on the keys and that different storage may have to be >> available on _all_ the nodes. >> >> Have any of the partial solutions mentioned in this email chain (or >> others) solved this problem? >> >> Claude >> >
