1. CS 140 Lecture Notes: Technology and Operating SystemsSlide 1 Technology Changes Mid-1980’s2009Change CPU speed15 MHz2 GHz133x Memory size8 MB4 GB500x Disk capacity30 MB500 GB16667x Disk transfer rate2 MB/s100 MB/s50x Network speed10 Mb/s1 Gb/s100x

2. CS 140 Lecture Notes: Technology and Operating SystemsSlide 2 RAMCloud Motivation: Technology Disk access rate not keeping up with capacity: ● Disks must become more archival ● More information must move to memory Mid-1980’s2009Change Disk capacity30 MB500 GB16667x Max. transfer rate2 MB/s100 MB/s50x Latency (seek & rotate)20 ms10 ms2x Capacity/bandwidth (large blocks) 15 s5000 s333x Capacity/bandwidth (1KB blocks) 600 s58 days8333x Jim Gray's rule5 min30 hrs360x

3. CS 140 Lecture Notes: Technology and Operating SystemsSlide 3 RAMCloud Overview ● Storage for datacenters ● 1000-10000 commodity servers ● 32-64 GB DRAM/server ● All data always in RAM ● Durable and available ● Performance goals:  High throughput: 1M ops/sec/server  Low-latency access: 5-10µs RPC Application Servers Storage Servers Datacenter

4. CS 140 Lecture Notes: Technology and Operating SystemsSlide 4 Example Configurations Today5-10 years # servers20004000 GB/server24GB256GB Total capacity48TB1PB Total server cost$3.1M$6M $/GB$65$6

5. CS 140 Lecture Notes: Technology and Operating SystemsSlide 5 Is RAMCloud Capacity Sufficient? ● Facebook: 200 TB of (non-image) data today ● Amazon: Revenues/year:$16B Orders/year:400M? ($40/order?) Bytes/order:1000-10000? Order data/year:0.4-4.0 TB? RAMCloud cost:$26-260K? ● United Airlines: Total flights/day:4000? (30,000 for all airlines in U.S.) Passenger flights/year:200M? Bytes/passenger-flight:1000-10000? Order data/year:0.2-2.0 TB? RAMCloud cost:$13-130K? ● Ready today for all online data; media soon

6. CS 140 Lecture Notes: Technology and Operating SystemsSlide 6 RAMCloud Research Issues ● Data durability/availability ● Fast RPCs ● Data model, concurrency/consistency model ● Data distribution, scaling ● Automated management ● Multi-tenancy ● Client-server functional distribution ● Node architecture

7. CS 140 Lecture Notes: Technology and Operating SystemsSlide 7