Re: [parisc-linux] raid-1 on boot disk

[Joel Soete <joel.soete@freebel.net>]

Hi Peter,


Peter Mottram wrote:
> Joel
> 
> I did some playing with this some time ago. To have all filesystems under
> md control then palo must understand two things:
> 
> 1. how to read the md filesystem to get the kernel (can use the F0
> partition for kernel to get round this)

I undurstand F0 is a special slice that PDC has to access to load ipl

> 
> 2. how to use md / filesystem
> 

Is a ramdisk (located in the special slice /boot) would not help?
I thought to this because of my read on the use of lvm and evms 
structure system disk. Both write a script to build such ramdisk.

> AFAIK these 2 things just don't work right now & Paul Bame has other more
> important things to do with palo right now.
> 
> The approach I take is to have a small / and small /boot as normal ext2
> partitions & automatically copy these over to spare / & /boot filesystems
> on mirror + hot spare disk each night.

Well ramdisk will avoid to have to do this 'manual' mirror on F0 and 
/boot but there are quasi-static and so easy to mirror with dd. On the 
contrary / is more dynamic so I do not see how do you realise the mirror 
  of this fs?

> All other filesystems (including
> swap) are on md. If I update the primary boot disk's F0 then I also
> update the F0 slice on mirror & spare disks. If the primary boot disk
> fails then the system will go down but then can boot off the mirror. Make
> sure you set up PRI and ALT boot paths correctly if you want this to
> happen automagically & make usre the script which copies / onto the
> mirror/spare modifies /etc/fstab appropriately!
> 
> R.
> PeteM

I am now much more confident, I will try to have a look in more details.

Many thanks for all information,
	Joel