7 ms·

This is really interesting and something I've been thinking about for a while now. The SEMANTICS[1] doc details what is and isn't supported from a POSIX filesys

• deleted 4y ago
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• FullyFunctional 4y ago
  Forgive the question but I never quite understood the point of S3. It seems it’s a terrible protocol but it’s designed for bandwidth. Why couldn’t they have used something like, say, 9P or Ceph? Surely I’m missing something fundamental. EDIT: In my personal experience with S3 it’s always been super slow.
  • Scarbutt 4y ago
    S3 is slow but at the same time low cost, if you want fast AWS has other alternatives but pricier.
    • mlhpdx 4y ago
      This is misleading. S3 is also incredibly fast. The former when you’re sequentially writing (or reading) objects and the latter when concurrently writing (or reading) vast numbers of them.
      • cyberax 4y ago
        That depends on what you consider "fast". EFS (the "serverless" NFS) has sub-millisecond operation latency. S3 is more in the 10-20ms range for most operations, with occasional spikes. BTW, if you need a pure Go client for NFSv4 (including AWS EFS), feel free to check my: https://github.com/Cyberax/go-nfs-client https://github.com/Cyberax/go-nfs-client
        • mlhpdx 4y ago
          We can write vast numbers and volume of objects to S3 per second using concurrent processes (spawn 1000 lambda invocations and try it). As long as I have the network bandwidth, I can push stuff essentially as fast as I want. Is that true for EFS? Handle limits. Network interface limits. Protocol limits. I’m not saying that S3 is perfect or even good for most workloads. However, it is most excellent when the workload fits.
          • chucky_z 4y ago
            Yea it kind of is! I've used EFS in real-world scenarios with more than 1,000 concurrent readers/writers. EFS's costs are just otherworldly compared to S3. If you need that interface though, it's a good (albeit expensive) choice.
            • orf 4y ago
              At one point we had a ~560tb EFS disk that ran a variety of mixed workloads (large and small files). It was untenable - raw reading/writing IO is OK, but metadata IO hits a brick wall and destroys the performance of the whole disk for all connections (not just ones accessing a particular partition/tree/whatever). In order to migrate off it and onto s3 I had to build a custom tool in rust that used libnfs directly to list the contents of the disk. We then launched a large number of lambdas to copy individual files to s3. It was fun, but in my experience EFS is only good if you have a very homogenous workload and are able to carefully optimise metadata IO. I wouldn’t recommend it - s3 is just cheaper, faster and better.
  • the8472 4y ago
    They have NFS (called EFS), but it's about 10x more expensive.
    • netfortius 4y ago
      Good luck mounting EFS in Windows.
      • mdaniel 4y ago
        Do you mean EFS specifically, or you find that NFS doesn't work? Because it was my recollection that Windows included NFS machinery natively
        • netfortius 4y ago
          EFS - this is what is being talked about here.
      • e12e 4y ago
        Apparently the nfs client in windows only supports nfs v3 - while efs only supports v4. The closest I found was: http://citi.umich.edu/projects/nfsv4/windows/readme.html http://citi.umich.edu/projects/nfsv4/windows/readme.html Seems odd that there are no commercial nfs v4 clients for windows? Might now be possible to mount via wsl? I see ractos has nfs client - but could not figure out which version...
      • profquail 4y ago
        WinFsp (FUSE for Windows) has an NFS driver: https://github.com/winfsp/nfs-win https://github.com/winfsp/nfs-win
      • otterley 4y ago
        AWS also offers FSx for Windows File Server, and FSx for ONTAP if you need remote Windows file service.
        • netfortius 4y ago
  • ary 4y ago
    When S3 was released the Internet was very different. Two of the things that stood out were: 1. It offered a resilient key/object store over HTTP. 2. By the standards of the day for bandwidth and storage it was (and to a certain extent still is) very inexpensive. Since then much of AWS has been built on the foundation of S3 and so its importance has changed from merely being a tool to basically a pervasive dependency of the AWS stack. Also, it very much is designed for objects larger than 1KB and for applications that need durable storage of many, many large objects. The key benefit, at least according to AWS marketing, is that you don't have to host it yourself.
  • supriyo-biswas 4y ago
    The problem is S3 is just a lexicographically ordered key value store with (what I suspect is) key-range partitions[1] for the key part and Reed-Solomon encoded blobs for the value part. In other words, it’s a glorified NoSQL database with no semantics that you’d typically expect of a file system, and therefore repeated writes are slow because any modification to an object involves writing a new version of the key along with its new object. [1] https://martinfowler.com/articles/patterns-of-distributed-systems/key-range-partitions.html https://martinfowler.com/articles/patterns-of-distributed-sy...
    • biorach 4y ago
      These aren't really problems tho, just features. These features may or may not be a problem for your application depending on your specific requirements. It's clear that for many many applications S3 works just fine. If you require file system semantics or interfaces (i.e. POSIX) or you update objects a lot or require non-sequential updates or.... then maybe it's not for you.
  • rakoo 4y ago
    S3 is straight HTTP, the most widespread API. It can be directly used on the browser, has libraries in pretty much every language, and can reuse the mountain of available software and frameworks for load-balancing, redirections, auth, distributed storage etc
  • spmurrayzzz 4y ago
    I think theres an interesting story in software ecosystems where there are two flavors of applications (which coexist) that prefer object stores over filesystems and vice versa. Good reference point for this I think exists in many modern video transcoding infrastructures. Using something like FSx [1] gives you a performant option for the use cases when the tooling involved prefers filesystem semantics. [1] https://aws.amazon.com/fsx/lustre/ https://aws.amazon.com/fsx/lustre/
  • aseipp 4y ago
    Because you don't have to allocate any fixed amount up front, and it's pay as you go. At the time when the best storage options you could get were fixed-size hard drives from VPS providers, this was a big change, especially on both the "very small" and "very large" ends of the spectrum. It has always spoken HTTP with a relatively straightforward request-signing scheme for security, so integration at the basic levels is very easy -- you can have signed GET requests, written by hand, working in 20 minutes. The parallel throughput (on AWS, at least) is more than good enough for the vast, vast majority of apps assuming they actually design with it in mind a little. Latency could improve (especially externally) but realistically you can just put an HTTP caching layer of some sort in front to mitigate that and that's exactly what everybody does. Ceph was also released many years after S3 was released. And I've never seen a highly performant 9P implementation come anywhere close to even third party S3 implementations. There was nothing for Amazon to copy. That's why everyone else copied Amazon, instead. It's not the most insanely hyper-optimized thing from the user POV (HTTP, etc) and in the past some semantics were pretty underspecified e.g. before full consistency guarantees several years ago, you only got "read your writes" and that's it. But it's not that hard to see why it's popular, IMO, given the historical context and use cases. It's hard to beat in the average case for both ease of use and commitment.
    • FullyFunctional 4y ago
      Thanks, it see now. Essentially I lacked the original context. I got many excellent answers and can’t reply everyone.
  • deathanatos 4y ago
    > In my personal experience with S3 it’s always been super slow. Numbers? I feel like it's been a while, but my experience was it is in the 50ms latency range. That's fast enough that you can do most things. Your page loads might not be instant, but 50ms is fast enough for a wide range of applications. The big mistake I see though is a lack of connection pooling: I find code going through the entire TCP connection setup, TLS setup, just for a single request, tearing it all down, and repeating. boto also enouranges some code patterns which result in GET bucket or HEAD object requests which you don't need and can avoid; none of this gives you good latency.
  • ignoramous 4y ago
    > Forgive the question but I never quite understood the point of S3. S3 and DynamoDB are essentially a decoupled BigTable; in that both are KV databases: One is used for high performance, small obj workloads; the other for high throughput, large obj workloads.
  • beebmam 4y ago
    Same with my experience. Not a fan
  • fnordpiglet 4y ago
    Simple api Absurdly cheap storage Extremely HA Absurdly durable Effectively unlimited bandwidth Effectively unbounded storage without reservation or other management Everything supports its api It’s not a file system. It’s a blob store. It’s useful for spraying vast amounts of data into it and getting vast amounts of data out of it at any scale. It’s not low latency, it’s not a block store, but it is really cheap and the scaling of bandwidth and storage and concurrency make it possible to build stuff like snowflake that couldn’t be built on Ceph in any reasonable way.
  • vbezhenar 4y ago
    Here are reasons I'm using S3 in some projects: 1. Cost. It might vary depending on vendor, but generally S3 is much cheaper than block storage, at the same time with some welcome guarantees (like 3 copies). 2. Pay for what you use. 3. Very easy to hand off URL to client rather than creating some kind of file server. Also works with uploads AFAIR. 4. Offloads traffic. Big files often are the main source of traffic on many websites. Using S3 allows to remove that burden. And S3 usually served by multiple servers which further increases speed. 5. Provider-independent. I think that every mature cloud offers S3 API. I think that there are more reasons. Encryption, multi-region and so on. I didn't use those features. Of course you can implement everything with your own software, but reusing good implementation is a good idea for most projects. You don't rewrite postgres, so you don't rewrite S3.
    • FullyFunctional 4y ago
      Thanks, I was unclear and meant only the protocol S3 not the service, but I see now that as a KV store it makes sense.
  • kbumsik 4y ago
    S3 works over HTTP, which means that it is designed to work over the internet. Other protocols you mentioned, including NFS, does not work well over the internet. Some of them are exclusively designed to work within the same network, or very sensitive to network latency.
• mlhpdx 4y ago
  I think you’re spot on: using multipart uploads, different sections of the ultimate object can be created out of order. Unfortunately, though, that’s subject to restrictions that require you to ensure all but the last part are sufficiently sized. I’m a little disappointed that this library (which is supposed to be “read optimized”) doesn’t take advantage of S3 Range requests to optimize read after seek. The simple example is a zip file in S3 for which you want only the listing of files from the central directory record at the end. As far as I can tell this library reads the entire zip to get that. I have some experience with this[1][2]. [1] https://github.com/mlhpdx/seekable-s3-stream https://github.com/mlhpdx/seekable-s3-stream [2] https://github.com/mlhpdx/s3-upload-stream https://github.com/mlhpdx/s3-upload-stream
  • simooooo 4y ago
    Wouldn’t you be maintaining your own list of what is in the zip offline at this point?
    • deleted 4y ago
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• Arnavion 4y ago
  I use a WebDAV server for storing backups (Fastmail Files). The server allows 10GB usage, but max file size is 250MB, and in any case WebDAV does not support partial writes. So writing a file requires reuploading it, which is the same situation as S3. What I did is: 1. Create 10000 files, each of 1MB size, so that the total usage is 10GB. 2. Mount each file as a loopback block device using `losetup`. 3. Create a RAID device over the 10000 loopback devices with `mdadm --build --level=linear`. This RAID device appears as a single block device of 10GB size. `--level=linear` means the RAID device is just a concatenation of the underlying devices. `--build` means that mdadm does not store metadata blocks in the devices, unlike `--create` which does. Not only would metadata blocks use up a significant portion of the 1MB device size, but also I don't really need mdadm to "discover" this device automatically, and also the metadata superblock does not support 10000 devices anyway (the max is 2000 IIRC). 4. From here the 10GB block device can be used as any other block device. In my case I created a LUKS device on top of this, then an XFS filesystem on the top of the LUKS device, then that XFS filesystem is my backup directory. So any modification of files in the XFS layer eventually results in some of the 1MB blocks at the lowest layer being modified, and only those modified 1MB blocks need to be synced to the WebDAV server. (Note: SI units. 1KB == 1000B, 1MB == 1000KB, 1GB == 1000MB.)
  • worewood 4y ago
    This is a very nice solution.
  • hardwaresofton 4y ago
    What a coincidence, I just recently did something similar. Did you run into any problems with discard/zeroing/trim support? This was a problem with sshfs — I can’t change the version/settings on the other side, and files seemed to simply grow and become more fragmented. I suspected WebDAV and Samba might have had been the solution but never looked into it since sshfs is so solid.
    • operator-name 4y ago
      If they're using LUKS then I think trimming/discard won't be possible.