Re: RAID superblock confusion

From: Richard Gooch (rgooch@ras.ucalgary.ca)
Date: Wed Apr 10 2002 - 17:49:06 EST


Mike Fedyk writes:
> On Wed, Apr 10, 2002 at 03:39:09PM -0600, Richard Gooch wrote:
> > Mike Fedyk writes:
> > > On Wed, Apr 10, 2002 at 02:37:48PM -0600, Richard Gooch wrote:
> > > >
> > > > The device is set up (i.e. SCSI host driver is loaded) long before I
> > > > do raidstart /dev/md/0
> > >
> > > But kernel auto-detection doesn't depend on the raidstart command. If
> > > things are setup correctly, you can remove that from your init scripts.
> >
> > I'm not (explicitely) using auto-detection. When I insmod the raid0
> > module, there are no messages about finding devices. All I get is:
> > md: raid0 personality registered as nr 2
> >
> > Only when I run raidstart do I get kernel messages about the devices.
> >
> > In any case, I should be able to move my devices around (especially
> > if /etc/raidtab is still correct), whether or not autostart is
> > running. The behaviour I'm observing is a bug (I assume it's not a
> > mis-feature, since the raidstart man page tells me that moving devices
> > around should be safe).
>
> Ehh, I ran into this a while ago. When you compile raid as modules
> it doesn't use the raid superblocks for anything except for
> verification. I took a quick glance at the source and the
> auto-detect code is ifdefed out if you compiled as a module.

Exactly where is this? A scan with find and grep don't reveal this.

> Ever since I have had raid compiled into my kernels.

This is my relevant .config:
CONFIG_MD=y
CONFIG_BLK_DEV_MD=y
CONFIG_MD_LINEAR=m
CONFIG_MD_RAID0=m
CONFIG_MD_RAID1=m
CONFIG_MD_RAID5=m
CONFIG_MD_MULTIPATH=m

                                Regards,

                                        Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca
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This archive was generated by hypermail 2b29 : Mon Apr 15 2002 - 22:00:17 EST