Search Again: Re: Capacity & RAM From: Peter Lalor Date: Monday, November 8, 1999 Time: 7:52:00 pm >From: "Men & Mice Support" <cbuxton@menandmice.com> > >At 10:16 AM -0600 11/5/99, Jerry Pasker-Systems Admin. wrote: > >I've been running > >my primary on a 6220 CD, (75Mhz 603, and the slowest PowerMac ever made) > >with 24MB of RAM (12 allocated to QDNS Pro 2.2.1) and have found that under > >a pretty good load (3-10 quirries per seccond) less RAM is better than more > >RAM. I'm only assuming that it's faster to search 1.5MB of cached records, > >and then resolve a name using an external server(s) than it is to sort > >through 11.5MB of cached records. > > > >I'm sure there has to be a guideline to setting RAM on different speeds of > >machines. Or is more allways better? Can anyone clarify this? > >In theory, more RAM is better, up to the point where the available >RAM is not all used. Beyond that, more RAM is simply unused. You can >check the free memory reading in the status window. > >However, that is a slow machine. > >Keep in mind that, no matter how fast the machine, there will be a >point where more RAM will slow it down. This is true of any type of >system that stores data in a table in RAM. Furthermore, when >resolving outside queries, QuickDNS Pro can also find the same >answers by the usual resolution routine, so the point of inefficiency >can be even lower, especially for slow machines. This is a very interesting point: Where does more processor outweigh more cache? It would seem that the answer depends on many factors, including the number of clients hitting the box (more will improve cache efficiencies) and how the root servers are doing. We had a larger cache on our secondary machine than our primary, but it's cache hit ratio was only about 30%. Our primary saw about a 75% cache hit ratio, with a smaller cache of about 8 Mb. Now, we're experimenting with a 55 Mb cache on the primary and the cache hit ratio is 80% after less than 24 hours in operation--but it shows 49 Mb free RAM (the machine has too much RAM, so what the hell). That server hosts well over 200 zones. But is it faster? Who knows? We'll have to watch it as it builds it's cache. DNS is not something I'm particularly inclined to assign much processor to, but it absolutely needs to be "fast enough". Peter Lalor Infoasis plalor@infoasis.com The San Francisco Bay Area's Macintosh 415-459-7991 Consultant and Internet Service Provider 415-459-7992 fax http://www.infoasis.com/

Messages In This Thread: Re: Capacity & RAM by Kurt Anderson on Nov 5, 1999 at 5:26:00 pm Re: Capacity & RAM by eric@micromaniac.com on Nov 5, 1999 at 5:47:00 pm Re: Capacity & RAM by Men & Mice Support on Nov 5, 1999 at 8:51:00 pm Re: Capacity & RAM by andrew kagan on Nov 5, 1999 at 9:55:00 pm Re: Capacity & RAM by Men & Mice Support on Nov 5, 1999 at 10:39:00 pm Re: Capacity & RAM by Peter Lalor on Nov 8, 1999 at 7:52:00 pm Re: Capacity & RAM by Jerry Pasker-Systems Admin. on Nov 8, 1999 at 8:14:00 pm Re: Capacity & RAM by Men & Mice Support on Nov 8, 1999 at 10:17:00 pm Re: Capacity & RAM by Peter Lalor on Nov 15, 1999 at 7:50:00 pm Re: Capacity & RAM by Men & Mice Support on Nov 15, 1999 at 10:26:00 pm