– 280k image requests/sec
– 300k req/sec

demo
– sports, travel, mail, news

internal expectations
– global

common challenges
– spped of light
– spikes
– cost
— space, paower, bandwidth, replication bandwidth
– partitioned network failures
— data center failures
— cap theorem
– consumer/user intuition
— replication is not bcp
—

mobstor & sherpa
– mobstor
— storage and delivery cloud
— cdns make sense when we have 90% cache hit rate
— features
— global
—- caching
—- protocol termination
—- authentication
—- content routing
— local
—- auto expiration
—- de-dup
—- object placement
—- re-replication
— layeruing
— dns gslb –> hardware vip –> scalable session mgr –> geo replication –> internal dns w/ loop feedback –> hardware vip –> local replication –> separate metadata replication
– sherpa
— simply put, it’s sharded mysql w/ replication
— stack: dns –> hadware vip –> scalable router & session mgr –> geo repl –> …

physics & econ for a global cloud
– what’s your target sla?
— distance + speed of light + network degredation = latency
— selective replication
– lessons learned
— intuition is usually wrong: let data drive data
— provide hoks, experimental fedback, and mobility
— n-way global repl is really expensive
— customers don’t understand 95/5 billing
— customers don’t understand cap theorem
— verify all provisioning
— there are a lot of non-hardware issues that can affect hardware performance
— strive for quality, but plan for failure

why care about y! cloud?
– commitment to open source
— componenet approach
— traffic server
— a handful of ppl for more than a year worked on open sourcing
— it’s a huge benefit to the community
— 400tb/day on 150 commodity boxs!
— would you want to build your company oin a web server that no one else uses?
— zookeeper

q/a
– why mobstor?
— mobstor solved the problem of brittl urls
– why dora?
— mobstor was built on filers
— dora was developed to replace filers
– commodity box costs
— < $4k / box
— highest density sata: 12 drives x 1tb/drive
– k/v store vs. relational db?
— everyone would love acid transactions, but they also need consistency & geo replication
– uses of k/v stores?
— mail uses it to assoc abuse records w/ ip addresses

about 150 ppl, 3/4+ full