Troubles with RAID and linux

[cliftonite]

I have this controller card for my 2 SATA drives and I am having issues with it. Linux detects the card and sees both of the drives attached to it. However it does not see that both of the drives are striped (via the cards bios). How can this be fixed?

 

[Bluestealth]

Likely to be the issue:

Most ATA RAID host adapters (except 3Ware Escalade, Adaptec 24x0, Areca, HP/Compaq, IBM ServeRAID, Intel SRC*/ICP Vortex, LSI Logic MegaRAID 150-4/150-6, and Tekram) turn out, upon examination, to not be real hardware RAID, but rather software/BIOS-dependent fakeraid. (I.e., missing hardware functionality is traditionally emulated inside idiosyncratic, undocumented, and proprietary software drivers, to hit low price points). Fakeraid is difficult to support in Linux ? absent either reverse-engineering, special proprietary drivers, or (rare) manufacturer cooperation. (HighPoint, LSI Logic, Nvidia, Promise, and VIA provide proprietary drivers to support their respective fakeraids. I personally would steer clear.)

Linux often cannot read existing fakeraid volumes on such host adapters, unless you're willing to use proprietary fakeraid drivers (where available). But unless you're dual-booting MS-Windows, you shouldn't care, because Linux's software RAID (kernel "md" driver) is much faster and more reliable. You're advised to blow away fakeraid volumes, use SATA drives as straight block devices, and enable Linux software RAID instead, during Linux installation.

I have heard great things about linux software raid...

 

[cliftonite]

Originally posted by: Bluestealth
Likely to be the issue:

Most ATA RAID host adapters (except 3Ware Escalade, Adaptec 24x0, Areca, HP/Compaq, IBM ServeRAID, Intel SRC*/ICP Vortex, LSI Logic MegaRAID 150-4/150-6, and Tekram) turn out, upon examination, to not be real hardware RAID, but rather software/BIOS-dependent fakeraid. (I.e., missing hardware functionality is traditionally emulated inside idiosyncratic, undocumented, and proprietary software drivers, to hit low price points). Fakeraid is difficult to support in Linux ? absent either reverse-engineering, special proprietary drivers, or (rare) manufacturer cooperation. (HighPoint, LSI Logic, Nvidia, Promise, and VIA provide proprietary drivers to support their respective fakeraids. I personally would steer clear.)

Linux often cannot read existing fakeraid volumes on such host adapters, unless you're willing to use proprietary fakeraid drivers (where available). But unless you're dual-booting MS-Windows, you shouldn't care, because Linux's software RAID (kernel "md" driver) is much faster and more reliable. You're advised to blow away fakeraid volumes, use SATA drives as straight block devices, and enable Linux software RAID instead, during Linux installation.

I have heard great things about linux software raid...

Thanks for the tip, guess I should have purchased a better card. I will look into the software raid though.

 

[Bluestealth]

Hardware raid is very expensive since it most times(always?) has a built in embedded processor on the board.

 

[nweaver]

this falls into a term coined here by...Drag or Nothinman a while back, iirc. We call this "winraid", in the same spirit as the old "winmodem"

 

[n0cmonkey]

Originally posted by: Bluestealth
Hardware raid is very expensive since it most times(always?) has a built in embedded processor on the board.

LSI Megaraid isn't too expensive, and OpenBSD supports it in their generic raid management system bioctl(8).