gnu@l5.uucp (John Gilmore) (09/13/85)
In article <1090@ulysses.UUCP>, smb@ulysses.UUCP (Steven Bellovin) writes: > I'm afraid you're grossly underestimating the CPU and disk throughput > requirements to put netnews on a machine. 2 of our 5 outbound links, on > a 750 used solely as a communications server (Ethernets, DMR-11s, laser > printers, etc.), are at high speed. Guess what -- one uuxqt running rnews > and there are no cycles left. If there are two, reading news will become > unpleasant. Those two plus a print job will totally kill the machine. Put it on a 68020. Vaxes are obsolete. (or is that why you're using them as comm servers?)
reid@Glacier.ARPA (Brian Reid) (09/14/85)
Glacier is a 750. Until today we had 2Mbytes (today we got a new backplane and we have 4Mbytes). We feed netnews to 12.5 sites (12 full feeds and one partial feed, plus about 20 local SF Bay feeds). Glacier is also the primary computing resource for about 100 people; during the day there are typically 30 jobs logged on, and at night there are perhaps 5 to 10 jobs logged on. The load factor on Glacier can get pretty grim at 3 in the afternoon, but netnews is never the culprit. Well, perhaps people reading news with "rn" (a resource hog) are part of the problem, but news transmission is not a problem. What I have found is that distribution of netnews over local area networks is essentially free on a machine like a VAX that has a high-performance asynchronous parallel data path to the network. The amount of CPU spent is almost unmeasurable; Glacier spends perhaps a total of 15 minutes a day, elapsed time, feeding these 7 LAN sites. Telephone line feeds, however, are very expensive. It burns a lot of CPU and causes a lot of context swaps. All of you know this, though. We don't do any phone line feeds during the day (except ba.seminars and things like that). If we tried to do phone line feeds during the day it would make a significant dent in our machine. The moral? Technology, such as our 3 and 10 megabit Ethernets and decent system software, can virtually eliminate the compute cost of transmitting news. There is still a cost associated with receiving news, caused by all of the forks and execs in recnews rnews, inews, unbatchnews, cunbatch, and all of those programs, but each site only has to do that once. I don't think 2400-baud phone lines would cure anything. Some hardware that enabled block synchronous transmisison over them would help a lot. -- Brian Reid decwrl!glacier!reid Stanford reid@SU-Glacier.ARPA