get a local experience, with minimal latency • Cache miss? get from load balancer • Logged out traffic almost never hits or affects logged in traffic • scale differently, control differently 10 Wednesday, July 18, 12
each machine with 400G storage • Hourly backups • Used as the main persistence layer for the site • Reads are from slaves, writes are from master • Logged out traffic will never have access the master 20 Wednesday, July 18, 12
shards • 16HD (100G) raid on each machine • 64G memory for each machine to provide out of memory index for all queries • Used for the Graph Engine + Scoring system 22 Wednesday, July 18, 12
on top of memcached • Queue services is hosted on Redis • Master / Slave replica • different redis cluster for different things 23 Wednesday, July 18, 12
in the scoring system • Grew ~170X last 18 months • Announced 1m registered users a month ago • hit 2m registered users 2 weeks agter 26 Wednesday, July 18, 12