Date: Thu, 7 Mar 1996 09:20:18 -0600 (CST) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: angio@aros.net (Dave Andersen) Cc: mtaylor@cybernet.com, hackers@freebsd.org Subject: Re: Proper FreeBSD news machine Message-ID: <199603071520.JAA13684@brasil.moneng.mei.com> In-Reply-To: <199603070345.UAA21122@terra.aros.net> from "Dave Andersen" at Mar 6, 96 08:45:28 pm
next in thread | previous in thread | raw e-mail | index | archive | help
> Lo and behold, Joe Greco once said: > > For comparison: > > > Let me sketch out my news operation here. I have multiple news peers, very > > few readers, I retain about a million articles (5 to 7 days retention).. > > We have 6 peers, and about the same amount of retention. > > > good deal, not because CPU was much of an issue. I'd say I was running > > 30-40% idle. That suggests a DX2/66 would be squeaky, though. The box is > > now a P90 and I notice a slight performance improvement. > > We're running on a P100 and typically have 90% idle, except during the > news.daily run (which admittedly takes about 7 hours or more). why so long? this is typically a clue to me to look at the RSS of expire and inn (or - easier - see how long the expire itself takes, see /var/log/news/expire.log, the start-to-end of expire should be no longer than 20 or 30 minutes MAX, particularly on a fast box). A shortage of memory will be immediately apparent because expire will take _forever_. > > > B) how much RAM? 32 Mb enough? > > > > Memory: 16MB + sizeof(history.pag) * 2MB + numclients * 1MB + numfeeds * 1MB. > > > > "clients" are expected simultaneous nnrp's. feeds are outbound feeds, > > innxmit or nntplink, no matter. sizeof(history.pag) in megabytes. > > It almost sounds like you developed this forumla before the > sharedactive patch meandered its way around. I'd have agreed with you > before (it would say we needed about 56 megs of ram, and we were actually > using about 49 during non-expire times), but the sharedactive patch > reduces the memory usage from 1.3M to .3M per client (roughly) on our > system. Obviously, the larger your active file, the more benefit you'll > achieve from this. On a 64MB machine, we run with about 28 megs used for > cache on average. This is with between 5 and 20 clients. The formula (slightly modified) dates from the days of C-news, and is neither INN- nor FreeBSD-specific. It is a really good ruler. FreeBSD actually requires a little _more_ RAM than the formula suggests, but it's still very ballpark. Things like sharedactive are nice, but in reality news _still_ needs lots of RAM available to cache data, so I might modify that to say "numclients * 1MB _with_ sharedactive" or "numclients * 2MB _without_". That is more complex, however, so I just leave my formula alone. ;-) > > it will begin to fight for pages with INN, and both your innd and expire > > processes will slow to a crawl. You also must factor in memory for other > > running processes (i.e. clients and feeds), and the OS itself needs some RAM > > (16MB, let's say, for kernel, cache, scratch, etc). > > Quite fair. I think you can squeak by on a bit less than this if > you're .. ahh, willing to put up with some burps and slowness, but given > that this machine is also going to act as a router -- I agree completely. > > > C) would separate SCSI busses help? (I plan to put a second 4.3Gb HD > > > in for the rest of the news spool) > > > > Go PCI SCSI if you can. Also, the more disks, the merrier (I have 14 but > > then I'm a performance freak). > > As a side note, be sure to keep the history* files on a separate spool > from the rest of the world. Do the same with the overfiew files if you > keep them. It'll make your life a lot happier. Keep _everything_ on separate spindles. > > > D) whose SCSI card has the 'best' performance? > > > > I've had good luck with the AHA3940 and NCR-810 based cards. The AHA2940 > > should work well too. > > It's a good performer, though we have occasional stability problems > with it. I think it's more due to one of the drives -- a 9gb micropolis > for storing alt.binaries -- than anything else. I haven't had any problems, but I'm mostly a Seagate shop. A few Micropolis drives out at Exec-PC lasted a few months and then died, I specifically asked that they be replaced with Barracudas and life is good.. > > Pay close attention to the memory advice. I see so many people try to get > > by without enough memory. It doesn't pay. I run Exec-PC's news operation > > and they try to squeeze 150-200 nnrp clients onto a box with 128MB RAM. > > They complain to me that it "takes forever to connect". I wonder why. ;-) > > That's masochism for you. :-) Actually, it's budget combined with "you can't FIT more than 128MB onto an ASUS Triton board" :-( ... Joe ------------------------------------------------------------------------------- Joe Greco - Systems Administrator jgreco@ns.sol.net Solaria Public Access UNIX - Milwaukee, WI 414/546-7968
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199603071520.JAA13684>