Some work on documentation towards v0.8
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title = "Benchmarks"
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weight = 10
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weight = 40
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With Garage, we wanted to build a software defined storage service that follow the [KISS principle](https://en.wikipedia.org/wiki/KISS_principle),
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title = "Goals and use cases"
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weight = 5
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weight = 10
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## Goals and non-goals
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Garage is a lightweight geo-distributed data store that implements the
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[Amazon S3](https://docs.aws.amazon.com/AmazonS3/latest/API/Welcome.html)
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object storage protocole. It enables applications to store large blobs such
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object storage protocol. It enables applications to store large blobs such
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as pictures, video, images, documents, etc., in a redundant multi-node
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setting. S3 is versatile enough to also be used to publish a static
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website.
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@ -20,6 +20,49 @@ In the meantime, you can find some information at the following links:
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- [an old design draft](@/documentation/working-documents/design-draft.md)
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## Request routing logic
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Data retrieval requests to Garage endpoints (S3 API and websites) are resolved
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to an individual object in a bucket. Since objects are replicated to multiple nodes
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Garage must ensure consistency before answering the request.
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### Using quorum to ensure consistency
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Garage ensures consistency by attempting to establish a quorum with the
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data nodes responsible for the object. When a majority of the data nodes
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have provided metadata on a object Garage can then answer the request.
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When a request arrives Garage will, assuming the recommended 3 replicas, perform the following actions:
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- Make a request to the two preferred nodes for object metadata
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- Try the third node if one of the two initial requests fail
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- Check that the metadata from at least 2 nodes match
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- Check that the object hasn't been marked deleted
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- Answer the request with inline data from metadata if object is small enough
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- Or get data blocks from the preferred nodes and answer using the assembled object
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Garage dynamically determines which nodes to query based on health, preference, and
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which nodes actually host a given data. Garage has no concept of "primary" so any
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healthy node with the data can be used as long as a quorum is reached for the metadata.
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### Node health
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Garage keeps a TCP session open to each node in the cluster and periodically pings them. If a connection
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cannot be established, or a node fails to answer a number of pings, the target node is marked as failed.
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Failed nodes are not used for quorum or other internal requests.
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### Node preference
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Garage prioritizes which nodes to query according to a few criteria:
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- A node always prefers itself if it can answer the request
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- Then the node prioritizes nodes in the same zone
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- Finally the nodes with the lowest latency are prioritized
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For further reading on the cluster structure look at the [gateway](@/documentation/cookbook/gateways.md)
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and [cluster layout management](@/documentation/reference-manual/layout.md) pages.
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## Garbage collection
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A faulty garbage collection procedure has been the cause of
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title = "Related work"
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weight = 15
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weight = 50
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## Context
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@ -9,6 +9,15 @@ Let's start your Garage journey!
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In this chapter, we explain how to deploy Garage as a single-node server
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and how to interact with it.
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## What is Garage?
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Before jumping in, you might be interested in reading the following pages:
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- [Goals and use cases](@/documentation/design/goals.md)
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- [List of features](@/documentation/reference-manual/features.md)
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## Scope of this tutorial
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Our goal is to introduce you to Garage's workflows.
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Following this guide is recommended before moving on to
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[configuring a multi-node cluster](@/documentation/cookbook/real-world.md).
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title = "Administration API"
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weight = 16
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weight = 60
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The Garage administration API is accessible through a dedicated server whose
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title = "Garage CLI"
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weight = 15
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weight = 30
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The Garage CLI is mostly self-documented. Make use of the `help` subcommand
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title = "Configuration file format"
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weight = 5
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weight = 20
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Here is an example `garage.toml` configuration file that illustrates all of the possible options:
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data_dir = "/var/lib/garage/data"
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block_size = 1048576
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block_manager_background_tranquility = 2
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replication_mode = "3"
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will not be deduplicated with chunks from newly uploaded files, meaning you
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might use more storage space that is optimally possible.
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### `block_manager_background_tranquility`
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This parameter tunes the activity of the background worker responsible for
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resyncing data blocks between nodes. The higher the tranquility value is set,
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the more the background worker will wait between iterations, meaning the load
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on the system (including network usage between nodes) will be reduced. The
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minimal value for this parameter is `0`, where the background worker will
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allways work at maximal throughput to resynchronize blocks. The default value
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is `2`, where the background worker will try to spend at most 1/3 of its time
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working, and 2/3 sleeping in order to reduce system load.
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### `replication_mode`
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Garage supports the following replication modes:
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85
doc/book/reference-manual/features.md
Normal file
85
doc/book/reference-manual/features.md
Normal file
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title = "List of Garage features"
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weight = 10
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### S3 API
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The main goal of Garage is to provide an object storage service that is compatible with the
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[S3 API](https://docs.aws.amazon.com/AmazonS3/latest/API/Welcome.html) from Amazon Web Services.
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We try to adhere as strictly as possible to the semantics of the API as implemented by Amazon
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and other vendors such as Minio or CEPH.
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Of course Garage does not implement the full span of API endpoints that AWS S3 does;
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the exact list of S3 features implemented by Garage can be found [on our S3 compatibility page](@/documentation/reference-manual/s3-compatibility.md).
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### Geo-distribution
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Garage allows you to store copies of your data in multiple geographical locations in order to maximize resilience
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to adverse events, such as network/power outages or hardware failures.
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This allows Garage to run very well even at home, using consumer-grade Internet connectivity
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(such as FTTH) and power, as long as cluster nodes can be spawned at several physical locations.
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Garage exploits knowledge of the capacity and physical location of each storage node to design
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a storage plan that best exploits the available storage capacity while satisfying the geo-distributed replication constraint.
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To learn more about geo-distributed Garage clusters,
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read our documentation on [setting up a real-world deployment](@/documentation/cookbook/real-world.md).
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### Flexible topology
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A Garage cluster can very easily evolve over time, as storage nodes are added or removed.
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Garage will automatically rebalance data between nodes as needed to ensure the desired number of copies.
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Read about cluster layout management [here](@/documentation/reference-manual/layout.md).
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### No RAFT slowing you down
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It might seem strange to tout the absence of something as a desirable feature,
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but this is in fact a very important point! Garage does not use RAFT or another
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consensus algorithm internally to order incoming requests: this means that all requests
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directed to a Garage cluster can be handled independently of one another instead
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of going through a central bottleneck (the leader node).
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As a consequence, requests can be handled much faster, even in cases where latency
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between cluster nodes is important (see our [benchmarks](@/documentation/design/benchmarks/index.md) for data on this).
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This is particularly usefull when nodes are far from one another and talk to one other through standard Internet connections.
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### Several replication modes
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Garage supports a variety of replication modes, with 1 copy, 2 copies or 3 copies of your data,
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and with various levels of consistency.
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Read our reference page on [supported replication modes](@/documentation/reference-manual/configuration.md#replication-mode)
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to select the replication mode best suited to your use case (hint: in most cases, `replication_mode = "3"` is what you want).
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### Web server for static websites
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A storage bucket can easily be configured to be served directly by Garage as a static web site.
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Domain names for multiple websites directly map to bucket names, making it easy to build
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a platform for your user's to autonomously build and host their websites over Garage.
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Surprisingly, none of the other alternative S3 implementations we surveyed (such as Minio
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or CEPH) support publishing static websites from S3 buckets, a feature that is however
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directly inherited from S3 on AWS.
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### Bucket names as aliases
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- the same bucket may have multiple names (useful when exposing websites for example)
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- bucket renaming is possible
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- Scoped buckets: 2 users can have a different bucket with the same name -> avoid collision. Helpful if you want to write an application that creates per-user bucket always with the same name.
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### Standalone/self contained
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### Integration with Kubernetes and Nomad
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Many node discovery methods: Kubernetes integration, Nomad integration through Consul
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### Support for changing IP addresses
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(as long as all nodes don't change their IP at the same time)
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### Cluster administration API
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### Metrics and traces
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### (experimental) K2V API
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title = "K2V"
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weight = 30
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weight = 70
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Starting with version 0.7.2, Garage introduces an optionnal feature, K2V,
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title = "Cluster layout management"
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weight = 10
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weight = 50
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The cluster layout in Garage is a table that assigns to each node a role in
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+++
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title = "Request routing logic"
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weight = 10
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+++
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Data retrieval requests to Garage endpoints (S3 API and websites) are resolved
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to an individual object in a bucket. Since objects are replicated to multiple nodes
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Garage must ensure consistency before answering the request.
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## Using quorum to ensure consistency
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Garage ensures consistency by attempting to establish a quorum with the
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data nodes responsible for the object. When a majority of the data nodes
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have provided metadata on a object Garage can then answer the request.
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When a request arrives Garage will, assuming the recommended 3 replicas, perform the following actions:
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- Make a request to the two preferred nodes for object metadata
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- Try the third node if one of the two initial requests fail
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- Check that the metadata from at least 2 nodes match
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- Check that the object hasn't been marked deleted
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- Answer the request with inline data from metadata if object is small enough
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- Or get data blocks from the preferred nodes and answer using the assembled object
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Garage dynamically determines which nodes to query based on health, preference, and
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which nodes actually host a given data. Garage has no concept of "primary" so any
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healthy node with the data can be used as long as a quorum is reached for the metadata.
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## Node health
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Garage keeps a TCP session open to each node in the cluster and periodically pings them. If a connection
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cannot be established, or a node fails to answer a number of pings, the target node is marked as failed.
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Failed nodes are not used for quorum or other internal requests.
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## Node preference
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Garage prioritizes which nodes to query according to a few criteria:
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- A node always prefers itself if it can answer the request
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- Then the node prioritizes nodes in the same zone
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- Finally the nodes with the lowest latency are prioritized
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For further reading on the cluster structure look at the [gateway](@/documentation/cookbook/gateways.md)
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and [cluster layout management](@/documentation/reference-manual/layout.md) pages.
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@ -1,6 +1,6 @@
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+++
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title = "S3 Compatibility status"
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weight = 20
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weight = 40
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+++
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## DISCLAIMER
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@ -1,6 +1,6 @@
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+++
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title = "Design draft"
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weight = 25
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title = "Design draft (obsolete)"
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weight = 50
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**WARNING: this documentation is a design draft which was written before Garage's actual implementation.
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title = "Load balancing data"
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weight = 10
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title = "Load balancing data (obsolete)"
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weight = 60
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**This is being yet improved in release 0.5. The working document has not been updated yet, it still only applies to Garage 0.2 through 0.4.**
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