WIP: garage_rpc: store layout version history

1 files changed, 32 insertions, 0 deletions

diff --git a/src/rpc/layout/mod.rs b/src/rpc/layout/mod.rs
new file mode 100644
index 00000000..122d4b65
--- /dev/null
+++ b/src/rpc/layout/mod.rs
@@ -0,0 +1,32 @@
+mod history;
+mod schema;
+mod tracker;
+mod version;
+
+pub use history::*;
+pub use schema::*;
+pub use version::*;
+
+// ---- defines: partitions ----
+
+/// A partition id, which is stored on 16 bits
+/// i.e. we have up to 2**16 partitions.
+/// (in practice we have exactly 2**PARTITION_BITS partitions)
+pub type Partition = u16;
+
+// TODO: make this constant parametrizable in the config file
+// For deployments with many nodes it might make sense to bump
+// it up to 10.
+// Maximum value : 16
+/// How many bits from the hash are used to make partitions. Higher numbers means more fairness in
+/// presence of numerous nodes, but exponentially bigger ring. Max 16
+pub const PARTITION_BITS: usize = 8;
+
+const NB_PARTITIONS: usize = 1usize << PARTITION_BITS;
+
+// ---- defines: nodes ----
+
+// Type to store compactly the id of a node in the system
+// Change this to u16 the day we want to have more than 256 nodes in a cluster
+pub type CompactNodeType = u8;
+pub const MAX_NODE_NUMBER: usize = 256;