1 / 16

Meta-Message: Technology Ratios Matter

Meta-Message: Technology Ratios Matter . Price and Performance change. If everything changes in the same way, then nothing really changes. If some things get much cheaper/faster than others, then that is real change. Some things are not changing much: Cost of people Speed of light …

alima
Download Presentation

Meta-Message: Technology Ratios Matter

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Meta-Message: Technology Ratios Matter • Price and Performance change. • If everything changes in the same way, then nothing really changes. • If some things get much cheaper/faster than others, then that is real change. • Some things are not changing much: • Cost of people • Speed of light • … • And some things are changing a LOT

  2. Trends: Moore’s Law • Performance/Price doubles every 18 months • 100x per decade • Progress in next 18 months = ALL previous progress • New storage = sum of all old storage (ever) • New processing = sum of all old processing. • E. coli double ever 20 minutes! 15 years ago

  3. Trends: ops/s/$ Had Three Growth Phases 1890-1945 Mechanical Relay 7-year doubling 1945-1985 Tube, transistor,.. 2.3 year doubling 1985-2000 Microprocessor 1.0 year doubling

  4. Trends: Gilder’s Law: 3x bandwidth/year for 25 more years • Today: • 40 Gbps per channel (λ) • 12 channels per fiber (wdm): 500 Gbps • 32 fibers/bundle = 16 Tbps/bundle • In lab 3 Tbps/fiber (400 x WDM) • In theory 25 Tbps per fiber • 1 Tbps = USA 1996 WAN bisection bandwidth • Aggregate bandwidth doubles every 8 months! 1 fiber = 25 Tbps

  5. How much does wire-time cost?$/Mbyte? Cost Time • Gbps Ethernet .2µ$ 10 ms • 100 Mbps Ethernet .3µ$ 100 ms • OC12 (650 Mbps) .003$ 20 ms • DSL .0006$ 25 sec • POTs .002$ 200 sec • Wireless: .80$ 500 sec

  6. Data delivery costs 1$/GB toady • Rent for “big” customers: 300$/megabit per second per month • Improved 3x in last 6 years (!). • That translates to 1$/GB you send. • You can mail a 160 GB disk for 20$. • That’s 16x cheaper • If overnight it’s 3 MBps. 3x160 GB ~ ½ TB

  7. Trends: Magnetic Storage Densities • Amazing progress • Ratios have changed • Capacity grows 60%/y • Access speed grows 10x more slowly

  8. 15 2 10 10 12 0 10 10 9 -2 10 10 6 -4 10 10 3 -6 10 10 Storage Hierarchy : Speed & Capacity vs Cost Tradeoffs Price vs Speed Size vs Speed Nearline Cache Tape Offline Main Tape Disc Secondary Online Online Secondary $/MB Tape Tape Disc Typical System (bytes) Main Offline Nearline Tape Tape Cache -9 -6 -3 0 3 -9 -6 -3 0 3 10 10 10 10 10 10 10 10 10 10 Access Time (seconds) Access Time (seconds)

  9. 10x better access time 10x more bandwidth 100x more capacity Data 25x cooler (1Kaps/20MB vs 1Kaps/500MB) 4,000x lower media price 20x to 100x lower disk price Scan takes 10x longer (3 min vs 45 min) DRAM/disk media price ratio changed 1970-1990 100:1 1990-1995 10:1 1995-1997 50:1 today ~ 6$/GB disk 100:1 600$/GB dram Storage Ratios Changed

  10. Data on Disk Can Move to RAM in 10 years 100:1 10 years

  11. The Five Minute Rule • Trade DRAM for Disk Accesses • Cost of an access (Drive_Cost / Access_per_second) • Cost of a DRAM page ( $/MB/ pages_per_MB) • Break even has two terms: • Technology term and an Economic term • Grew page size to compensate for changing ratios. • Now at 5 minutes for random, 10 seconds sequential

  12. The 5 Minute Rule Derived Breakeven: RAM_$_Per_MB = _____DiskPrice . PagesPerMB T x AccessesPerSecond Disk Access Cost /T DiskPrice . AccessesPerSecond ( )/T Cost a RAM Page RAM_$_Per_MB PagesPerMB $ T =TimeBetweenReferences to Page T = DiskPrice x PagesPerMB . RAM_$_Per_MB x AccessPerSecond

  13. Plugging in the Numbers • Trend is longer times because disk$ not changing much, RAM$ declining 100x/decade 5 Minutes & 10 second rule

  14. Summarizing storage rules of thumb (1) • Moore’s law: 4x every 3 years 100x more per decade • Implies 2 bit of addressing every 3 years. • Storage capacities increase 100x/decade • Storage costs drop 100x per decade • Storage throughput increases 10x/decade • Data cools 10x/decade • Disk page sizes increase 5x per decade.

  15. Summarizing storage rules of thumb (2) • RAM:Disk and Disk:Tape cost ratios are 100:1 and 3:1 • So, in 10 years, disk data can move to RAM since prices decline 100x per decade. • A person can administer a million dollars of disk storage: that is 1TB - 100TB today • Disks are replacing tapes as backup devices.You can’t backup/restore a Petabyte quicklyso geoplex it. • Mirroring rather than Parity to save disk arms

  16. Meta-Message: Technology Ratios Matter • Price and Performance change. • If everything changes in the same way, then nothing really changes. • If some things get much cheaper/faster than others, then that is real change. • Some things are not changing much: • Cost of people • Speed of light • … • And some things are changing a LOT

More Related