I discussed this offline with Claude, he is no longer working on this. It's a pity. I think this is a very valuable thing. Commitlog's archiving and restore may be able to use the relevant code if it is completed.
Patrick McFadin <pmcfa...@gmail.com>于2024年9月20日 周五上午2:01写道： > 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 >>>> >>>
