North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: SONET ring questions
At 10:34 PM 10/16/98 -0700, Alan Hannan wrote: > >> For total system uptime >> 90.0% (one nine or less) Desktop systems. >> 99.0% (two nines) Intermediate business systems >> 99.9% (three nines) Most business data systems and workgroup servers >> 99.99% (four nines) High-end business systems and your friendly >> neighborhood telco >> 99.999% (five nines) Bank Data Centers and Telco Data Centers, some ISPs >> 99.9999% (six nines) Only God and Norad live here. >> 99.99999% (seven nines) Even God doesn't have pockets this deep. > > What's your source for this data? You mean, besides 22 years in the system design and development trade? Well, you can start with the various companies I have worked for. Then the manufacturing specs on the various systems. My last analysis involved two-headed server setup on HP 9000 series T520 with MC service guard and shared RAID5. HP guarantees that at three nines. With the right add-ons I got it to four nines (Complete second site in AZ, 1500 miles away). Very expensive. Five nines would have broken the budget, that was Wells Fargo. Northrup/Grumman MD-18 flight-line support. The PacBell broadband system was quad redundant data centers in Fairfield and San Diego. I was hired in as the Techinical Architect for that system. Again, HP equipment. That system would have hit five nines, or better, in production. I think we were pushing past $16M on that system, thirty-six specially configured T520's plus RAID packs. Various systems I worked on in Patrice Carrol's org in MCI COS (Garden of the Gods facility), including the Fraud Management System. This stuff is more art than science, too many non-deterministic variables. Experience is the only thing that counts. It tells you which formulaii to use and when they have a chance of working. I should have my web-site up again this week-end, we're converting to FastTrack with LiveWire, in addition to Apache-SSL/mod_perl. ___________________________________________________ Roeland M.J. Meyer, ISOC (InterNIC RM993) e-mail: <mailto:[email protected]>[email protected] Internet phone: hawk.mhsc.com Personal web pages: <http://www.mhsc.com/~rmeyer>www.mhsc.com/~rmeyer Company web-site: <http://www.mhsc.com/>www.mhsc.com/ ___________________________________________ I bet the human brain is a kludge. -- Marvin Minsky
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