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diff --git a/doc/book/reference-manual/routing.md b/doc/book/reference-manual/routing.md deleted file mode 100644 index aec637cc..00000000 --- a/doc/book/reference-manual/routing.md +++ /dev/null @@ -1,45 +0,0 @@ -+++ -title = "Request routing logic" -weight = 10 -+++ - -Data retrieval requests to Garage endpoints (S3 API and websites) are resolved -to an individual object in a bucket. Since objects are replicated to multiple nodes -Garage must ensure consistency before answering the request. - -## Using quorum to ensure consistency - -Garage ensures consistency by attempting to establish a quorum with the -data nodes responsible for the object. When a majority of the data nodes -have provided metadata on a object Garage can then answer the request. - -When a request arrives Garage will, assuming the recommended 3 replicas, perform the following actions: - -- Make a request to the two preferred nodes for object metadata -- Try the third node if one of the two initial requests fail -- Check that the metadata from at least 2 nodes match -- Check that the object hasn't been marked deleted -- Answer the request with inline data from metadata if object is small enough -- Or get data blocks from the preferred nodes and answer using the assembled object - -Garage dynamically determines which nodes to query based on health, preference, and -which nodes actually host a given data. Garage has no concept of "primary" so any -healthy node with the data can be used as long as a quorum is reached for the metadata. - -## Node health - -Garage keeps a TCP session open to each node in the cluster and periodically pings them. If a connection -cannot be established, or a node fails to answer a number of pings, the target node is marked as failed. -Failed nodes are not used for quorum or other internal requests. - -## Node preference - -Garage prioritizes which nodes to query according to a few criteria: - -- A node always prefers itself if it can answer the request -- Then the node prioritizes nodes in the same zone -- Finally the nodes with the lowest latency are prioritized - - -For further reading on the cluster structure look at the [gateway](@/documentation/cookbook/gateways.md) -and [cluster layout management](@/documentation/reference-manual/layout.md) pages.
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