On Sat, 2001-12-22 at 23:04, Stephen Liu wrote: > Hi All People, > > Merry X'mas > > I have some further RAID questions to ask : > > 1) Can ATA-133 hard drive be used on RAID controller available on market > such RAID 0, 1, 0+1 etc. with cable for ATA100/ATA133. No special designed > controller is needed ? >
Yes, but there is no support for the fake hardware RAID in 8.1. Read support is sort-of there to allow compatibility with reading a Windows RAID but there is no support for using the software RAID in the PROM on the RAID "controller" that is actually a BIOS extenstion. You folks don't know you are paying $30-60 extra to a hardware vendor for a BIOS extension PROM? Or that the software in there is protected by kaw from reverse engineering so that being compatible with the WinRAID controller is at the mercy of whatever scraps of infor the manufacturer will give us? Do yourselves a favor. Don't buy the fake RAID unless you really need it for windows. Even then, real hardware RAID is preferable and available here: http://www.arcoide.com/ And for info on the open source RAID project to provide some compatibility with the WinRAIDs, go here: http://people.redhat.com/arjanv/pdcraid/ If you want to know which controllers support full 133 cable speed, check this: http://www.linux-ide.org/chipsets.html Of course you can use a 133 drive on a lesser controller--no harm done. You just cannot get full speed out of it. Finally, if you are considering buying new IDE equipment, be aware of which of it is actively supporting linux by checking here: http://www.linux-ide.org/endorsements.html In particular, one of the brands not listed is a source of continuing problems just to get the disk geometry right and should never, ever be used above ATA / 33 on any machine though they rate themselves for 66, 100 and 133 without the hardware on board the drive to meet the standard. And if you ask them they will tell you in no uncertain terms that they don't support linux. Linux has its own software RAID which covers modes 0, 1, 4, and 5, 3 is best left to real hardware. For most linices, the drivers are the same, right out of the kernel, plain vanilla and written to the _standards_ defined by the hardware manufacturers. More than one hardware manufacturer meets those standards with a combination of corner-curring dodges on the hareware and their own third-party drivers (for windows) to make up for the deficiencies of the hardware. Naturally they work only with windows because no one who is economizing will see any cost-effectiveness in writing for a system that has only 5% market share on desktops,(and the folks who use servers for real business buy something else anyway). One even offers a detection service direct to windows users to pre-warn you when your drive is about to fail. You can search under "Data Lifeguard" to find it, but it works only with Windows. We have a similar feature by activating the SMART technology on your drives, but just local to your computer. Now, insofar as ATA/xx is concerned, sometimes the highest possible xx is not a good idea. Before 8.2, I will issue another versiuon of drakopt to run the tests to find the best speed for your drives. There are many cases where a higher speed _reduces_ performance because the noise causes more repeat requests, and there are many situations where ATA/66 actually outperforms ATA/100 on an individual machine, and some cases where ATA/33 outperforms ATA/66 (most severe I saw was a WD200AB on a MaxData computer set up by RH to run ATA/66 which provided 1.86Mb/s. At ATA/33 with optimizing settings determined by DrakOpt, it was getting 9.62 Mb/s.) Remember that higher speeds mean smaller signals in terms of total charge, and the energy in these signals are now small compared with a secondary cosmic ray. Please, I have answered this question enough. Next time someone else answer with a link to the archives pointing to this or any of the other articles. Civileme > 2) RAID 0 > If I have 6 discs and the controller has only 2 channels. How to make > connection ? 1 master and 2 slaves for each channel ? Or need a > controller with at least 3 channels > > 3) RAID 1 > a) Question same as RAID 0, about discs connection : > in order to achieve two concurrent separate reads per mirrored pair or two > duplicate writes per mirrored pair ? > b) What does it mean "One Write or two Reads possible per mirrored pair" > > 4) RAID 3 to my understanding : being very high read and write data > transfer rate > a) Controller design is fairly complex : is it awailable on market ? Not > ordered made component ? > b) Connect question for 3 hard discs > c) What does it mean "Low ratio of ECC (Parity) disks to data disks means > high efficiency" ? > > Thanks in advance. > > B.R. > Stephen Liu > > > > ------------=_1009094810-11608-1173 > Want to buy your Pack or Services from MandrakeSoft? > Go to http://www.mandrakestore.com
Want to buy your Pack or Services from MandrakeSoft? Go to http://www.mandrakestore.com
