Showing posts from August, 2018

(08/13/2018) Mt. Rainier Summit

14k ft over 3 days

Next up
(2019) expeditions seminar north cascades
(2020) aconcagua
(2021) peru
(2020) denali

Reading “Spanner: Google's Globally Distributed Database”

IntroductionScalable, Globally-distributed database Shards data across many sets of Paxos state machines in global datacentersTwo features Externally consistent R / WGlobally consistent REnabled by globally-meaningful commit timestamps that reflect serialization order that satisfies external consistency (If a T1 commits before another T2 starts, then T1's commit timestamp is smaller than T2). Enabler is TrueTime API. Implementation (Structure of Spanner's Implementation, feature set, engineering decisions) Spanserver Software Stack  Responsible for between 100-1000 instances of a data structure called tablet (bag of key to timestamp mappings), stored in a set of B-tree like files and a write-ahead log in a DFS called Colossus. Implements a single Paxos state machine on top of each tablet to support replicationThese state machines implement a consistently replicated bag of mappings; each mapping state of each replica is stored in its corresponding tablet. Writes initiate the Pax…