fd filesystem and RAID1

fd filesystem and RAID1

[Ninti Systems]

I've been able to do everything involved in setting up a simple RAID1
with 2 IDE disks on Slackware 9.1 except get it to actually keep working
on reboot. 

I installed on one disk, built 'degraded' RAID1 devices on the second
disk, copied data, etc. I can hot add devices from the original disk to
the RAID arrays. RAID devices in /etc/fstab come up (in degraded mode)
on boot.

The problem is that hot-added devices never stick, the RAID arrays are
always degraded again on reboot. 

mdadm complains of missing superblocks. I have read the man page but
can't see how to manage superblocks (create/delete) if this is even
possible.

I'm wondering if have to make the original install partitions type 'fd'
as well as those on the second disk? 

Re: fd filesystem and RAID1

[Daniel Pittman]

On 03 Apr 2004, Ninti Systems wrote:
> I've been able to do everything involved in setting up a simple RAID1
> with 2 IDE disks on Slackware 9.1 except get it to actually keep
> working on reboot.
> 
> I installed on one disk, built 'degraded' RAID1 devices on the second
> disk, copied data, etc. I can hot add devices from the original disk
> to the RAID arrays. RAID devices in /etc/fstab come up (in degraded
> mode) on boot.
> 
> The problem is that hot-added devices never stick, the RAID arrays are
> always degraded again on reboot. 
> 
> mdadm complains of missing superblocks. I have read the man page but
> can't see how to manage superblocks (create/delete) if this is even
> possible.
> 
> I'm wondering if have to make the original install partitions type
> 'fd' as well as those on the second disk?

The kernel auto-discovery will only probe a partition that has type
'fd', so if you want both parts of the mirror to work, both need to be
type 'fd'.

     Daniel

-- 
Democracy is ever eager for rapid progress, and the only
progress which can be rapid is progress made down hill.
        -- Sir James Jeans

Re: fd filesystem and RAID1

[Ninti Systems]

Thanks for your patient replies Daniel. I'm not having a lot of luck
with RAID1 on Slackware, and will probably have to go back to RedHat9's
comfy GUI.

I have followed the instructions in your initial reply, but haven't been
able to set up even a non-root RAID device using mdadm that doesn't try
to resync on every reboot. This is with all fs types as 'fd'. The fault
lies with me of course, not your instructions. which I must be
misreading somehow.

I'm thinking of trying mkraid and using a startup script to get RAID
going. Or maybe just mirroring data to the second disk with rsync.


On Mon, 2004-04-05 at 10:28, Daniel Pittman wrote:
> On 03 Apr 2004, Ninti Systems wrote:
> > I've been able to do everything involved in setting up a simple RAID1
> > with 2 IDE disks on Slackware 9.1 except get it to actually keep
> > working on reboot.
> > 
> > I installed on one disk, built 'degraded' RAID1 devices on the second
> > disk, copied data, etc. I can hot add devices from the original disk
> > to the RAID arrays. RAID devices in /etc/fstab come up (in degraded
> > mode) on boot.
> > 
> > The problem is that hot-added devices never stick, the RAID arrays are
> > always degraded again on reboot. 
> > 
> > mdadm complains of missing superblocks. I have read the man page but
> > can't see how to manage superblocks (create/delete) if this is even
> > possible.
> > 
> > I'm wondering if have to make the original install partitions type
> > 'fd' as well as those on the second disk?
> 
> The kernel auto-discovery will only probe a partition that has type
> 'fd', so if you want both parts of the mirror to work, both need to be
> type 'fd'.
> 
>      Daniel
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Re: fd filesystem and RAID1

[Ninti Systems]

> > 
> > The kernel auto-discovery will only probe a partition that has type
> > 'fd', so if you want both parts of the mirror to work, both need to be
> > type 'fd'.

I tried doing this to partitions on both IDE devices pre-install
(Slackware saw them all as md devices, install impossible), and I also
tried changing the original install disk's partitions over to 'fd' type
after copying their content to the md device (the second disk also all
'fd' type).

But whatever I do the arrays never have usable superblocks, are always
degraded and always want to resync on boot.

Thanks for all your help, but I'm starting to get over this RAID on
Slackware thing. I think I'll reconsider my distro (RedHat) or my backup
strategy (rsync).

Thanks again

Re: fd filesystem and RAID1

[Daniel Pittman]

On 05 Apr 2004, Ninti Systems wrote:
>> > 
>> > The kernel auto-discovery will only probe a partition that has type
>> > 'fd', so if you want both parts of the mirror to work, both need to
>> > be type 'fd'.
> 
> I tried doing this to partitions on both IDE devices pre-install
> (Slackware saw them all as md devices, install impossible), and I also
> tried changing the original install disk's partitions over to 'fd'
> type after copying their content to the md device (the second disk
> also all 'fd' type).
> 
> But whatever I do the arrays never have usable superblocks, are always
> degraded and always want to resync on boot.

Hrm.  I am sorry that things have proved to be such a challenge.  One
thing to note, of course, is that a software RAID root file system is
much harder to use than any other partition done as software RAID.

You may have better luck by creating a couple of small partitions and
working with those as an "extra" drive, until you resolve the problems.

One final note:  I found the 'mdadm' tool a *vast* improvement over the
traditional RAID tools for Linux.  

> Thanks for all your help, but I'm starting to get over this RAID on
> Slackware thing. I think I'll reconsider my distro (RedHat) or my
> backup strategy (rsync).

RedHat certainly seems to offer good graphical tools for managing this
sort of thing, which can be very useful while you learn how things work.

There is nothing wrong with using a helping hand in software rather than
by email. :)

Good luck.
     Daniel

-- 
All that you suspect about women's friendships is true. We talk about dick size.
        -- Cynthia Heimel