[CentOS] Centos5: RAID1 on root/boot? [+lilo mkinitrd issues]

Mon Apr 23 06:49:27 UTC 2007
Pekka Savola <pekkas at netcore.fi>


On Sun, 22 Apr 2007, William L. Maltby wrote:
> On Sun, 2007-04-22 at 21:40 +0300, Pekka Savola wrote:
>> Hi,
>> I did a command-line upgrade of a RHL73 server to Centos 5.  It was a
>> bit rocky road, but in the end it was successful.
>> There's one thing that bugged me.  I'm using software RAID1 consisting
>> of /dev/hd{a,c}.  No LVM or anything fancy, a number of /dev/mdX
>> partitions, including the root (+/boot).
>> I'd have preferred to continue using lilo as it works more easily with
>> RAID1 root/boot setups.  The deployment guide for Centos5 claims to
>> support RAID1 boot partitions (RHEL4 didn't, and provided a pointer a
>> site in UK which no longer works for more info), it's not clear how
>> exactly a redundant boot block configuraton is achieved with that --
>> so that if you remove the primary drive, it'll still boot.
>> Anyone have pointers for this?
>> [I've gone through a number of sites with various hacks how to install
>> grub on both disks, but I'm not quite sure which ones are valid, and
>> whether those are needed anymore]
> This has been touched on several times in the CentOS mailings. Did you
> also search CentOS? If not, ISTR that there are answers there. For grub,
> of course.
> <snip>

Yes, though apparently the 'Search' button on the frong page doesn't 
search mailing lists, it probably should.

Yes, I've done extensive searching. The problem is that there are 
something like 3-4 ways to achieve the desired end results and those 
ways apply to various versions of grub.

It's not obvious to me which approach is "The Way" for Centos/RHEL5 
(preferably tested and working; if it doesn't work, a bug should be 
filed).  Some mailings seem to hint that it should 'just work' with 
Centos5 due to changes in Grub, all those postings happened before 
Centos5/RHEL5 was even released.

For the record, here are IMHO the best links were:

http://forums.fedoraforum.org/showthread.php?t=49266 (more detail)

Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings