On Sat, Feb 07, 2004 at 11:32:55PM -0800, Roger Chrisman wrote: > > fun stuff > > RAID 1 is one strategy for getting 'faster' read going. > > Redundant Array of Inexpensive Devices (RAID) comes in various flavors. > > RAID 1 is a flavor where you take two disks of the same size and have the > computer treat them as one disk. The computer mirrors the identical data onto > both disks and can read one part of a file from one drive simultaneously as > it reads the other part of the file from the other drive. Thus reading the > whole file in half (roughly half I think) the time it would take to read the > whole file from one drive. > > Of course rather than paying for two drives, you might want to just pay for > one faster drive, more RAM, or some other speed enhancer. If you already have > the drives sitting around thought, RAID 1 is something you might like. > > Linux can do Software Raid. So you do not need to buy special hardware > controllers. > > If you do Software Raid, to achieve the speed advantage you should put the two > disks that make up your one logical device on separate cables. > > md0 stands for 'zeroeth (1st) multiple device,' a notional drive made up of > more than one real drives. > > I did Software RAID 1 with two drives and SuSE 9's Installer for my desktop > box (just before converting to the Debian way :-). It was kinda tricky. I > actually bought a 2 Channel Controller PCI card so that I could have four > total (including the two on my mother board) channels and thus not have more > than one drive per cable. I have four drives you see. CD drive, back up IDE > hard drive, and two IDE drives as my RAID 1 md0. > > These fancy tricks might not be worth it though if your system bus is 33MHz. > My two PIII servers have 33MHz system bus (PCI host bridge). So I don't think > it would be worth the trouble on my servers. > > Someone who knows more about RAID please tell me if I am mistaken about that.
Oh, I think it'll be useful. Remember, PCI at 32bits and 33Mhz can transfer 132MBytes/sec, and your drives won't fill that up. Also, once you start seeking, your disk throughput goes down radically. -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
