HostRaid support on FreeBSD

Dag-Erling Smørgrav des at
Wed Jun 23 14:12:41 GMT 2004

Maxim Sobolev <sobomax at> writes:
> Well, my knowelege about internals of software RAID controllers is
> quite limited, but as long as I know they are no more than BIOS with
> UI for setting up RAIDs and interface to main BIOS that hides internal
> RAID structure allowing to boot off the RAID. Also they provide some
> persistent storage for RAID configuration, I assume either in some
> controller's NVRAM or on the HDDs.

The configuration is always stored on-disk, otherwise it wouldn't be
possible to recover from controller failure.

> Therefore, the same set of GEOM
> RAID modules can work with different software RAID controllers (SCSI,
> ATA, SATA etc) if there will be a standard way to extract this info
> from the controller's driver, and present it in some common
> format. That's what I am talking about.

You're kicking down open doors.  This problem has already been solved
for Vinum, which is conceptually identical from a GEOM point of view.

Dag-Erling Smørgrav - des at

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