FreeBSD Preferred RAID controllers

[Gabe]

--- On Sat, 2/14/09, Matthew Seaman <m.seaman at infracaninophile.co.uk> wrote:

> From: Matthew Seaman <m.seaman at infracaninophile.co.uk>
> Subject: Re: FreeBSD Preferred RAID controllers
> To: nrml at att.net
> Cc: freebsd-questions at freebsd.org
> Date: Saturday, February 14, 2009, 8:30 AM
> Gabe wrote:
> > --- On Mon, 2/9/09, Matthew Seaman
> <m.seaman at infracaninophile.co.uk> wrote:
> > 
> >> From: Matthew Seaman
> <m.seaman at infracaninophile.co.uk>
> >> Subject: Re: FreeBSD Preferred RAID controllers
> >> To: nrml at att.net
> >> Cc: freebsd-questions at freebsd.org
> >> Date: Monday, February 9, 2009, 3:08 PM
> >> Gabe wrote:
> >>
> >>> Now with a gstripe+gmirror setup, would it be
> possible
> >> to fail a
> >>> specific drive on purpose? I mean fail a
> (good) drive,
> >> pull it out,
> >>> replace it and rebuild(?) it. I know I know,
> but humor
> >> me.
> >>
> >> Yes.
> >>
> >> 	Cheers,
> >>
> >> 	Matthew
> >>
> >> Well, to 'fail' the drive, you'ld have
> to
> >> physically pull the drive
> >> from the chassis which will involve a power cycle
> unless
> >> you've got
> >> hot-swap drives.  Of course, you should confirm
> that your
> >> system will
> >> boot with the RAID in a degraded state and that
> rebuilding
> >> the RAID will
> >> continue even if interrupted by a reboot. 
> gmirror(8)
> >> passes those
> >> tests.  You do have to type some commands to get a
> mirror
> >> to rebuild
> >> (examples are shown in the man page) unlike some
> hardware
> >> RAIDs where
> >> simply inserting an unused disk is sufficient.
> >>
> >> -- Dr Matthew J Seaman MA, D.Phil.                
>   7
> >> Priory Courtyard
> >>                                                 
> Flat 3
> >> PGP: http://www.infracaninophile.co.uk/pgpkey    
> Ramsgate
> >>                                                 
> Kent, CT11
> >> 9PW
> > 
> > Hello again all,
> > 
> > So I wanted to test out gmirror on software RAID so I
> installed a completely vanilla FBSD 7, as base an install as
> you can get, it hasn't even been on the network. Anyway,
> I did the following upon first boot to get gmirror going:
> > 
> > # sysctl kern.geom.debugflags=17
> > 
> > Then:
> > # gmirror label -vb round-robin gm0 /dev/ad0
> > 
> > Then:
> > # gmirror load
> > 
> > Then:
> > # echo 'geom_mirror_load="YES"'
> >> /boot/loader.conf
> > 
> > Then I edited /etc/fstab to show:
> > /dev/mirror/gm0s1b    none        swap    sw          
>    0       0
> > /dev/mirror/gm0s1a    /           ufs     rw          
>    1       1
> > /dev/mirror/gm0s1e    /tmp        ufs rw      0   0
> > /dev/mirror/gm0s1f    /usr        ufs rw      2   2
> > /dev/mirror/gm0s1d    /var        ufs     rw          
>    2       2
> > 
> > I then rebooted the system, once I setup the mirror:
> > 
> > # gmirror insert gm0 /dev/ad1
> > # gmirror status
> > 
> > and it shows as COMPLETE. Okay, here comes the
> annoying part, I've got hot-swappable bays and I went
> ahead and pulled the drive. I then tried to write to the
> disk so that it realizes the disk is no longer there:
> > 
> > # touch file
> > 
> > once I do that and execute: gmirror status it shows as
> degraded. All fine and dandy. However when it comes time to
> pop the drive back in the drive is not recognized at all. I
> mean, the green light on the bay comes on so it definitely
> makes a connection but then thats it, atacontrol list
> doesn't list it and gmirror status still shows the same,
> degraded.
> > 
> > What gives? I wonder if this is hardware related? Bios
> related even? Any clues?
> 
> See atacontrol(8)
> 
>    # atacontrol list
> 
> shows what your system knows is there
> 
>    # atacontrol attach X
> 
> where X is the channel number, probes and attaches any
> devices on that
> channel in exactly the same way it is done at system boot.
> 
> See camcontrol(8) if you've got SCSI drives.
> 
> 	Cheers,
> 
> 	Matthew
> 
> -- 
> Dr Matthew J Seaman MA, D.Phil.                   7 Priory
> Courtyard
>                                                   Flat 3
> PGP: http://www.infracaninophile.co.uk/pgpkey     Ramsgate
>                                                   Kent,
> CT11 9PW

They're SATA drives. The two drives are on the same channel when using atacontrol list. I'm unsure that atacontrol attach ata0 would work but I'll give it a shot, hopefully that works. I'll report back.

Thanks again