Reorganize documentation for new website (#213)

This PR should be merged after the new website is deployed.

- [x] Rename files
- [x] Add front matter section to all `.md` files in the book (necessary for Zola)
- [x] Change all internal links to use Zola's linking system that checks broken links
- [x] Some updates to documentation contents and organization

Co-authored-by: Alex Auvolat <alex@adnab.me>
Reviewed-on: https://git.deuxfleurs.fr/Deuxfleurs/garage/pulls/213
Co-authored-by: Alex <alex@adnab.me>
Co-committed-by: Alex <alex@adnab.me>

1 files changed, 56 insertions, 0 deletions

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+title = "Goals and use cases"
+weight = 5
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+
+## Goals and non-goals
+
+Garage is a lightweight geo-distributed data store that implements the
+[Amazon S3](https://docs.aws.amazon.com/AmazonS3/latest/API/Welcome.html)
+object storage protocole. It enables applications to store large blobs such
+as pictures, video, images, documents, etc., in a redundant multi-node
+setting. S3 is versatile enough to also be used to publish a static
+website.
+
+Garage is an opinionated object storage solutoin, we focus on the following **desirable properties**:
+
+  - **Self-contained & lightweight**: works everywhere and integrates well in existing environments to target [hyperconverged infrastructures](https://en.wikipedia.org/wiki/Hyper-converged_infrastructure).
+  - **Highly resilient**: highly resilient to network failures, network latency, disk failures, sysadmin failures.
+  - **Simple**: simple to understand, simple to operate, simple to debug.
+  - **Internet enabled**: made for multi-sites (eg. datacenters, offices, households, etc.) interconnected through regular Internet connections.
+
+We also noted that the pursuit of some other goals are detrimental to our initial goals.
+The following has been identified as **non-goals** (if these points matter to you, you should not use Garage):
+
+  - **Extreme performances**: high performances constrain a lot the design and the infrastructure; we seek performances through minimalism only.
+  - **Feature extensiveness**: we do not plan to add additional features compared to the ones provided by the S3 API.
+  - **Storage optimizations**: erasure coding or any other coding technique both increase the difficulty of placing data and synchronizing; we limit ourselves to duplication.
+  - **POSIX/Filesystem compatibility**: we do not aim at being POSIX compatible or to emulate any kind of filesystem. Indeed, in a distributed environment, such synchronizations are translated in network messages that impose severe constraints on the deployment.
+
+## Use-cases
+
+*Are you also using Garage in your organization? [Open a PR](https://git.deuxfleurs.fr/Deuxfleurs/garage) to add your use case here!*
+
+### Deuxfleurs
+
+[Deuxfleurs](https://deuxfleurs.fr) is an experimental non-profit hosting
+organization that develops Garage. Deuxfleurs is focused on building highly
+available infrastructure through redundancy in multiple geographical
+locations. They use Garage themselves for the following tasks:
+
+- Hosting of [main website](https://deuxfleurs.fr), [this website](https://garagehq.deuxfleurs.fr), as well as the personal website of many of the members of the organization
+
+- As a [Matrix media backend](https://github.com/matrix-org/synapse-s3-storage-provider)
+
+- To store personal data and shared documents through [Bagage](https://git.deuxfleurs.fr/Deuxfleurs/bagage), a homegrown WebDav-to-S3 proxy
+
+- In the Drone continuous integration platform to store task logs
+
+- As a Nix binary cache
+
+- As a backup target using `rclone`
+
+The Deuxfleurs Garage cluster is a multi-site cluster currently composed of
+4 nodes in 2 physical locations. In the future it will be expanded to at
+least 3 physical locations to fully exploit Garage's potential for high
+availability.