Re: fedora 17 cant see my raid 5 disk array
From the error about "bios" raid, he's using fakeraid for sure.
kubiej21: You've made the terrifying mistake of setting up a pretend raid5 array. In fact, your "raid" card is nothing besides a typical non-raid sata controller. All raid function is implemented in the DRIVER, and not actually within the raid card.
What this means is that you will experience dismal performance out of your array.
There are three kinds of raid;
and FAKE RAID.
Fake raid is software raid that PRETENDS to be hardware raid.
Hardware raid has the PERFORMANCE advantage, CROSS PLATFORM advantage, and portability DISADVANTAGE.
Software raid has the PORTABILITY advantage (it isn't tied to the controller), cross platform DISADVANTAGE, and performance DISADVANTAGE.
Fakeraid has the PERFORMANCE DISADVANTAGE, CROSS PLATFORM DISADVANTAGE, and the PORTABILITY DISADVANTAGE. There is NO advantage at all. It is slow, and it is tied to the controller.
My recommendation is to back up that data and build a software array. If the array needs to be accessed by multiple non-cooperative operating systems, either pick up a genuine RAID card, or you may consider using fakeraid in a MIRRORING arrangement. DMRAID is typically able to handle fakeraid mirrors, but raid5 is a bit much since it depends on specific implementation details.
Note that fakeraid came about as a sales-feature for budget low-end cards. Junk like the promise fasttrak card which would sell for about $50.
A real raid card will have a much higher starting price. Used to start at around $500+ for a 4-port raid card. Now you can start to see entry level LSI cards for around $250.
Last edited by droidhacker; 18th June 2012 at 05:10 PM.