Re: raid controllers and suse9.1
From: Juhan Leemet (juhan_at_logicognosis.com)
Date: Sat, 17 Jul 2004 23:24:30 -0200
(seem to be several threads on this?)
On Sat, 17 Jul 2004 13:26:03 -0400, cybercrypt13 wrote:
> Anthony wrote:
>> On Sat, 17 Jul 2004 10:43:54 -0400, cybercrypt13 wrote:
>>> Armand Chin Kwie Joe wrote:
>>>> [quoted text muted]
>>> Actually as it was explained to me by SUSE, its not them that doesn't
>>> support these types of cards but rather the new 2.6 kernel now uses
>>> things that the old 2.4 kernel just ignored and as a result it will not
>>> software raid cards. I never realized they were viewed as software raid
>>> when you had to buy a hardware card to place in the machine but for some
>>> reason they are. I've had to resort to getting SUSE software RAID 1
>>> figured out and so far have not had much luck...
>> I found getting software raid 1 installed on suse9.1 to be relatively
>> easy. However,I did this during the install process when I partitoned the
>> drives. I am not sure about creating a raid 1 after the install....
> Ok, I already admitted that I've never setup a software RAID so please
> elaborate. Lets take this example please:
> / 2gb
> SWAP 1gb
> /usr 5 gb
> /home 15gb
> Now I setup my first drive to look like this, what do I now do with the
> second drive in order to get it to work in a RAID 1 configuration.
I would partition the 2nd drive identically to the 1st.
Then you have to define /etc/raidtab (to associate partitions into md<n>)
Then you have to edit /etc/fstab (the mount points) to use md devices
Splicing this into the boot process is a bit more involved. See HOWTOs.
(from above, I probably couldn't help you any more; I'm running SuSE 8.2)
In summary, what has to happen on bootup (from mirrored root):
1) BIOS has to find a disk to boot (usually a sequence) 1/2 of mirror
2) MBR invokes LILO or GRUB which loads kernel, mounts some files
3) kernel starts up RAID metadevices (and remounts them?)
4) system finishes booting up, using md devices for root partition(s)
these md devices are dual mirrors of (e.g.) hda, hdb
NOTE: AFAIK you cannot boot from S/W RAID5: chicken/egg problem.
-- Juhan Leemet Logicognosis, Inc.