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Neat project and great post. One thing I'd like to point out is that there is another mechanism for implementing userspace filesystems in Linux: V9FS. FUSE ha

by aray 13y ago

Neat project and great post. One thing I'd like to point out is that there is another mechanism for implementing userspace filesystems in Linux: V9FS. FUSE has a lot of documentation -- much of it in various stages of bitrot -- and many of the comments here point to other FUSE projects as well! The underlying mechanisms for FUSE are pretty convoluted and difficult, so much more than trivial examples can break the abstractions afforded by the libraries like the one used in the post. V9FS is in contrast exceedingly simple and basically unchanged. And, yes, it's based on the Plan 9 filesystem protocols :) http://v9fs.sourceforge.net/ http://v9fs.sourceforge.net/

marbu 13y ago
This is interesting. I'm aware of the fact that some plan 9 protocols were ported to linux, but are you suggesting that this v9fs is a replacement for fuse in common use cases? Do you know about simple comparision of fuse and v9fs implementation of the same userspace filesystem?
- aray 13y ago
  V9FS and FUSE both enable userspace filesystem drivers. They are actually pretty interchangeable for 99% of use cases, and the rest of those cases are where you'd directly interact with both, so it wouldn't be fair to compare a FUSE library abstraction with V9FS. FUSE is too complicated to directly interact with, so everyone (OP included) is using libraries and abstractions on top of it. So what you'd really be comparing is that abstraction, as well as possibly how it limits actual FUSE interaction. Additionally, the performance of these abstractions is hard to predict, as many do lots of work (threads/IPC/etc) silently in the background, so the apparent workload on your filesystem driver is far from actual workload. V9FS is simple enough that drivers often just talk it directly. The protocol is a simple RPC mechanism, and parallelism happens naturally. As far as a direct comparison example, I don't know of one.

by aray 13y ago

marbu 13y ago

This is interesting. I'm aware of the fact that some plan 9 protocols were ported to linux, but are you suggesting that this v9fs is a replacement for fuse in common use cases? Do you know about simple comparision of fuse and v9fs implementation of the same userspace filesystem?

aray 13y ago
V9FS and FUSE both enable userspace filesystem drivers. They are actually pretty interchangeable for 99% of use cases, and the rest of those cases are where you'd directly interact with both, so it wouldn't be fair to compare a FUSE library abstraction with V9FS. FUSE is too complicated to directly interact with, so everyone (OP included) is using libraries and abstractions on top of it. So what you'd really be comparing is that abstraction, as well as possibly how it limits actual FUSE interaction. Additionally, the performance of these abstractions is hard to predict, as many do lots of work (threads/IPC/etc) silently in the background, so the apparent workload on your filesystem driver is far from actual workload. V9FS is simple enough that drivers often just talk it directly. The protocol is a simple RPC mechanism, and parallelism happens naturally. As far as a direct comparison example, I don't know of one.