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Re: [PLUG] Raid Basics (was: Linux Raid)
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> Hold up. I'm considering buying a DFI AD73 mo'bo' with RAID. The specs
> are here: http://sj.dfi.com.tw/product/fetch.asp?theValue=AD73%20RAID
>
> If the built-in controller is RAID enabled, how is that software-based
RAID?
The controller is nothing but a standard ATA controller, the 'RAID' portion
is entirely located in the firmware. The firmware is executed by the CPU. In
Windows 9X, where accessing a device through the BIOS information was
acceptable, you could insall onto one of these RAIDs, format, move files,
etc, without ever loading a driver. In NT and Linux, among others, a device
driver is needed. Basically, the Windows and Linux drivers re-create what
the firmware was doing, along with adding a few other tweaks.
> With these controllers, is it possible to partition the larger drive so
> that is can stripe with a smaller drive while still allowing access to
> the remaining space on the larger drive?
No. That is only possible with OS-based RAID, where the drives are seen as
normal by the OS and as a RAID by software. Promise/Highpoint-type firmware
RAID presents the RAID itself to the OS. Anything not defined as a RAID is
not accessable. It MAY be possible to set up a RAID like so:
20GB primary master (HDE)
8GB secondary master (HDG)
16GB (2 * 8GB) RAID0 across all of HDG and the first 8GB of HDE
(/dev/ataraid/d0p1)
12GB single disk partition HDE1 in the remaining 12GB of HDE
-- However, this is EXTREMELY inadvisable, as ANY accesses to the beginning
of plain disk HDE will quite possibly destroy the beginning of the RAID
partition. The possibility of this method is also entirely in the hands of
your particular implementation, as well. Some controllers may let you do
this with no trouble, but no OS I've ever tried has been able to 'see'
unallocated disk space on one of my RAID disks (Fasttrak 100, HPT370,
Fasttrak TX4).
Rich 'Forge' Mingin
> >'RAID' users are actually using a form of bootable software RAID,
courtesy
> >of their Promise Fasttrak and HPT onboard controllers. There's nothing
wrong
> >with these, I'm using a Fasttrak TX4 myself, but they should not be
confused
> >with true hardware RAID.
> >
>
>
>
> ______________________________________________________________________
> Philadelphia Linux Users Group - http://www.phillylinux.org
> Announcements-http://lists.phillylinux.org/mail/listinfo/plug-announce
> General Discussion - http://lists.phillylinux.org/mail/listinfo/plug
>
>
>
______________________________________________________________________
Philadelphia Linux Users Group - http://www.phillylinux.org
Announcements-http://lists.phillylinux.org/mail/listinfo/plug-announce
General Discussion - http://lists.phillylinux.org/mail/listinfo/plug
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