RE: Linux performance

Agree with Art. Amount of cache on Raid Controller, Writeback or writetrough, Stripe size, number of spindles, SCSI ULTRA #, PCI Bus speed, IO Chip/Mhz {Most use to have Intel 960} all have a big influence on performance. Also look at Megaraid controllers. Last tested beat Mylex and easier to set up. This was 3 years ago and for sure could have changed by now. DTP + Compaq also high perf controllers. Adaptec cheaper level that will suite Linux. -----Original Message----- From: Art S. Kagel [mailto:kagel@bloomberg.net] Sent: Wednesday, 20 December, 2000 1:18 AM To: informix-list@iiug.org Subject: Re: Linux performance John, are you using Linux RAID? It beats hell out of the CPUS! Faster than a speeding bullet but it gets that speed by sucking up all the CPU cycles it can get. Linux built in software RAID is only really good for configuring a dedicated fileserver not for any machine that needs the CPU also. For serious RAID get a hardware RAID10 solution like ICP Vortex or Mylex. Those controllers have their own CPUs and offload all the RAID work to them leaving the main system CPUs alone. In a recently published test, between Linux software RAID5 and Vortex RAID5 on a Linux box, Linux gave better throughput but maxed the two test machine CPUs out doing it. Art S. Kagel Obnoxio The Clown wrote: > > In the year of Our Lord Tue, 12 Dec 2000 14:50:53 -0700, John Miller > <jmiller@itc.nrcs.usda.gov> broke a vow of silence to utter: > > > > >We have a 4-700 Mhz cpu Intel box with the 2.2.16 linux Kernel(SuSE > >7.0). > >We have the number of CPU's set to 3 for Informix, 1 less then the max. > >The problem is once we get more then 4 users hitting the database hard > >the system starts to crawl. iostat shows the CPU's running at 80 to > >100%. > >Does anyone know if this is the best performance we can get? > > > >We are using RAID 1+0 on two controllers and raw space. > > Bloody hell!! How is the CPU load spread? Mostly user, or lots of sys or wio? > > Can you post output for: > > onstat -p > onstat -P | tail -5 > onstat -R > onstat -F > onstat -g seg > onstat -d > onstat -D > onstat -m > onstat -c> sar 5 12