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notes/byz.md

@@ -170,6 +170,35 @@ Clients are assumed to talk to different leaders.
 
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+# Chubby
+
+- explicitly talk about replicated log as base of dist systems
+- basically a key-value store
+
+## Optimizations:
+- multipaxos
+- batching mult values in single instance
+- master leases 
+  - ensure reads do not have to go through consensus
+- boosting leader seq numbers periodicaly to avoid old masters trying
+  to re-take the lead
+- snapshots: log is record of steps to achieve a state
+  - that state can be used to substitute for the log
+  - but logs are under control of the system, while snapshots under
+    control of app
+	
+
+
+## Multi-op
+- came out of compare-and-swap requirement
+- guard: list of tests of various slots
+- t_op: DB operations to execute if guard TRUE
+- f_op: DB operations to execute if guard FALSE
+
+---------------------------------------------------------------------
+
+
+
 
 ## Byzantine consensus: Two Lieutenants Problem