Thanks for reviving this one! On Wed, Sep 18, 2024 at 12:06 AM guo Maxwell <cclive1...@gmail.com> wrote:
> 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 >>> >>
