> At its core, Torus is a library with an interface that appears as a traditional file, allowing for storage manipulation through well-understood basic file operations. Coordinated and checkpointed through etcd’s consensus process, this distributed file can be exposed to user applications in multiple ways. Today, Torus supports exposing this file as block-oriented storage via a Network Block Device (NBD). We also expect that in the future other storage systems, such as object storage, will be built on top of Torus as collections of these distributed files, coordinated by etcd.
Am I understanding correctly that this is a file-based API? Distributing a POSIX filesystem effectively is very challenging, particularly since most applications that use them aren't written with CAP in mind; they don't expect a lot of basic operations to block for extended periods and fail in surprising ways, and they very often perform poorly when operations that are locally quick end up much slower over a network.
To be concrete:
> Today’s Torus release includes manifests using this feature to demonstrate running the PostgreSQL database server atop Kubernetes flex volumes, backed by Torus storage.
It will be interesting to see how well this performs and how it behaves in the face of single-node failures and network congestion.
Virtualized, network block devices have all the same problems I described -- even worse, because the abstraction coneys even less about what an application is trying to do.
No. The difference is, that with network block devices you are usually only allow accessing the block device once. That's an easier problem than mapping POSIX file system semantics!
Am I understanding correctly that this is a file-based API? Distributing a POSIX filesystem effectively is very challenging, particularly since most applications that use them aren't written with CAP in mind; they don't expect a lot of basic operations to block for extended periods and fail in surprising ways, and they very often perform poorly when operations that are locally quick end up much slower over a network.
To be concrete:
> Today’s Torus release includes manifests using this feature to demonstrate running the PostgreSQL database server atop Kubernetes flex volumes, backed by Torus storage.
It will be interesting to see how well this performs and how it behaves in the face of single-node failures and network congestion.