On Sun July 20 2003 5:39 pm, Philipp Thomas wrote:
"Carlos E. R."
[20 Jul 2003 15:32:44 +0200]: 1) Cheap raid cards, or motherboard things, are not really hardware raid solutions. 2) They need support from the OS as a driver, be it windows, Linux, whatever. 2b) They don't work as raid without such drivers 4) A "pseudo hardware raid" like this, with the proper personality, can (or could) be used both from windows and Linux - of course, if formated with a filesystem both understand. 5) They are probably less flexible than a Linux software raid. 6) They are perhaps faster :-?
Am I approximately correct? Incorrect?
Yes, this is mostly correct.
ob 4) Both OS's will see the actual RAID array just like normal drives/partitiions. But each OS can only use that part of the RAID array that's formatted with a filesystem it supports.
ob 6) I can't tell. I've never dealt with those things (at least not as RAID array). If I needed RAID, I'd use a 3ware card. That's real RAID in Hardware at affordable prices.
Philipp
From personal experience, but without using a stopwatch and comparing two separate installations, RAID (with apologies to Philipp for abbreviating this from "Not Really Real RAID"), I would only say it seems not to be slower. It is clearly not the difference in getting a new MB/CPU and cetera. Test results I had seen earlier (Anandtech, maybe?) suggested a performance increase of maybe 10% if you were lucky in striped mode, maybe a couple of % if anything in mirrored mode, though reads were a little quicker than writes. Personally, I do not see (Philipp's hated) RAID as a solution to performance issues, but rather as a solution to other issues, eg, lots of old disks hanging around, each too small to use alone, and so on. Regards, Richard