Lessons learned from [email_address] David  P. Anderson January 31, 2002
SETI@home Operations data recorder screensavers science DB user DB WU storage splitters DLT tapes data server result queue...
Radio SETI projects   25 0.5 0.25 320 70 3e-23 Beta (Harvard) 150 0.6 0.4 100 33 1e-24 SERENDIP (Berkeley) 25,000 0.07 to ...
History and statistics <ul><ul><li>Conceived 1995, launched April 1999 </li></ul></ul><ul><ul><li>Funding: TPS, DiMI, nume...
Public-resource computing <ul><li>Original: GIMPS, distributed.net </li></ul><ul><li>Commercial: United Devices, Entropia,...
Characterizing SETI@home <ul><li>Fixed-rate data processing task </li></ul><ul><li>Low bandwidth/computation ratio </li></...
Be prepared for crowds <ul><li>Server scalability </li></ul><ul><li>Dealing with excess CPU time </li></ul><ul><li>Redunda...
Network bandwidth costs money <ul><li>SSL to campus: 100 Mbps, free, unloaded </li></ul><ul><li>Campus to ISP: 70 Mbps, no...
How to get and retain users <ul><li>Graphics are important </li></ul><ul><ul><li>But monitors  do  burn in </li></ul></ul>...
Reward users <ul><li>PDF certificates </li></ul><ul><li>Milestone pages and emails </li></ul><ul><li>Leader boards (overal...
Let users express themselves <ul><li>User profiles </li></ul><ul><li>Online poll </li></ul><ul><li>Newsgroup (sci.astro.se...
Users are competitive <ul><li>Patched clients, benchmark wars </li></ul><ul><li>Results with no computation </li></ul><ul>...
Anything can be reverse engineered <ul><li>Patched version of client </li></ul><ul><ul><li>efforts at self-checksumming </...
Users will help if you let them <ul><li>Web-site translations </li></ul><ul><li>Add-ons </li></ul><ul><ul><li>Server proxi...
Client: mechanism, not policy <ul><li>Error handling, versioning </li></ul><ul><li>Load regulation </li></ul><ul><ul><li>L...
Cross-platform is manageable <ul><li>Windows, Mac are hard </li></ul><ul><li>GNU tools and POSIX rule </li></ul>
Server reliability/performance <ul><li>Hardware </li></ul><ul><ul><li>Air conditioning, RAID controller </li></ul></ul><ul...
What’s next for public computing? <ul><li>Better handling of large data </li></ul><ul><ul><li>Network scheduling </li></ul...
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20020131-P2P-Anderson.ppt

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Transcript of "20020131-P2P-Anderson.ppt"

  1. 1. Lessons learned from [email_address] David P. Anderson January 31, 2002
  2. 2. SETI@home Operations data recorder screensavers science DB user DB WU storage splitters DLT tapes data server result queue acct. queue garbage collector tape archive, delete tape backup master DB redundancy checking RFI elimination repeat detection web site CGI program web page generator
  3. 3. Radio SETI projects 25 0.5 0.25 320 70 3e-23 Beta (Harvard) 150 0.6 0.4 100 33 1e-24 SERENDIP (Berkeley) 25,000 0.07 to 1200 50 2.5 33 3e-25 [email_address] 200 1 1 2000 0.005 (1000 stars) 1e-26 Phoenix (SETI Inst.) Computing power (GLFOPs) Frequency resolution (Hz) Max drift rate (Hz/sec) Frequency Range (MHz) Sky coverage (%sky) Sensitivity Name
  4. 4. History and statistics <ul><ul><li>Conceived 1995, launched April 1999 </li></ul></ul><ul><ul><li>Funding: TPS, DiMI, numerous companies </li></ul></ul><ul><ul><li>3.5M users (.5M active), 226 countries </li></ul></ul><ul><ul><li>40 TB data recorded, processed </li></ul></ul><ul><ul><li>25 TeraFLOPs average over last year </li></ul></ul><ul><ul><li>No ET signals yet, but other results </li></ul></ul>
  5. 5. Public-resource computing <ul><li>Original: GIMPS, distributed.net </li></ul><ul><li>Commercial: United Devices, Entropia, Porivo, jxtp, Popular Power </li></ul><ul><li>Academic, open-source </li></ul><ul><ul><li>Cosm, folding@home, SETI@home II </li></ul></ul><ul><li>The peer-to-peer paradigm </li></ul>
  6. 6. Characterizing SETI@home <ul><li>Fixed-rate data processing task </li></ul><ul><li>Low bandwidth/computation ratio </li></ul><ul><li>Independent parallelism </li></ul><ul><li>Error tolerance </li></ul>
  7. 7. Be prepared for crowds <ul><li>Server scalability </li></ul><ul><li>Dealing with excess CPU time </li></ul><ul><li>Redundant computing </li></ul><ul><ul><li>Deals with cheating, malfunctions </li></ul></ul><ul><ul><li>Control by changing computation </li></ul></ul><ul><li>Moore’s Law is true (causes same problems) </li></ul>
  8. 8. Network bandwidth costs money <ul><li>SSL to campus: 100 Mbps, free, unloaded </li></ul><ul><li>Campus to ISP: 70 Mbps, not free </li></ul><ul><li>First: load limiting at 25 Mbps </li></ul><ul><li>Now: no limit, zero priority </li></ul><ul><li>How to adapt load to capacity? </li></ul><ul><li>What’s the break-even point (1GB per CPU day) </li></ul>
  9. 9. How to get and retain users <ul><li>Graphics are important </li></ul><ul><ul><li>But monitors do burn in </li></ul></ul><ul><li>Teams: users recruit other users </li></ul><ul><li>Keep users informed </li></ul><ul><ul><li>Science news </li></ul></ul><ul><ul><li>System management news </li></ul></ul><ul><ul><li>Periodic project emails </li></ul></ul>
  10. 10. Reward users <ul><li>PDF certificates </li></ul><ul><li>Milestone pages and emails </li></ul><ul><li>Leader boards (overall, country, …) </li></ul><ul><li>Class pages </li></ul><ul><li>Personal signal page </li></ul>
  11. 11. Let users express themselves <ul><li>User profiles </li></ul><ul><li>Online poll </li></ul><ul><li>Newsgroup (sci.astro.seti) </li></ul><ul><li>Message boards </li></ul><ul><li>Learn about users </li></ul>
  12. 12. Users are competitive <ul><li>Patched clients, benchmark wars </li></ul><ul><li>Results with no computation </li></ul><ul><li>Intentionally bad results </li></ul><ul><li>Team recruitment by spam </li></ul><ul><li>Sale of accounts on eBay </li></ul><ul><li>Accounting is tricky </li></ul>
  13. 13. Anything can be reverse engineered <ul><li>Patched version of client </li></ul><ul><ul><li>efforts at self-checksumming </li></ul></ul><ul><li>Replacement of FFT routine </li></ul><ul><li>Bad results </li></ul><ul><ul><li>Digital signing: doesn’t work </li></ul></ul><ul><ul><li>Techniques for verifying work </li></ul></ul>
  14. 14. Users will help if you let them <ul><li>Web-site translations </li></ul><ul><li>Add-ons </li></ul><ul><ul><li>Server proxies </li></ul></ul><ul><ul><li>Statistics DB and display </li></ul></ul><ul><li>Beta testers </li></ul><ul><li>Porting </li></ul><ul><li>Open-source development </li></ul><ul><ul><li>(will use in SETI@home II) </li></ul></ul>
  15. 15. Client: mechanism, not policy <ul><li>Error handling, versioning </li></ul><ul><li>Load regulation </li></ul><ul><ul><li>Let server decide </li></ul></ul><ul><ul><li>Reasonable default if no server </li></ul></ul><ul><li>Put in a level of indirection </li></ul><ul><ul><li>Separate control and data </li></ul></ul>
  16. 16. Cross-platform is manageable <ul><li>Windows, Mac are hard </li></ul><ul><li>GNU tools and POSIX rule </li></ul>
  17. 17. Server reliability/performance <ul><li>Hardware </li></ul><ul><ul><li>Air conditioning, RAID controller </li></ul></ul><ul><li>Software </li></ul><ul><ul><li>Database server </li></ul></ul><ul><li>Architect for failure </li></ul><ul><li>Develop diagnostic tools </li></ul>
  18. 18. What’s next for public computing? <ul><li>Better handling of large data </li></ul><ul><ul><li>Network scheduling </li></ul></ul><ul><ul><li>Reliable multicast </li></ul></ul><ul><li>Expand computation model </li></ul><ul><li>Multi-application platform </li></ul><ul><li>Economic model </li></ul>
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