[clue-tech] md driver software raid and bootstrapping

[mike havlicek]

Hello All,

Any suggestions on configuring drive mappings when mirroring a boot partition? In the scenario I am looking at I am using grub with ext3 on the mdX devices (md driver raid1). I am curious about the scenario where during a component failure, an unattended reboot is triggered before the failed component is replaced (which is most likely going to be the one where bootstrapping normally begins :).

I suppose that in whatever "mysterious" scanning that occurs, the method is
not random, but BIOS specific --> undesirable experimentation? Or is there a general rule for getting the (hdx,y) grub representation and the linux representations (e.g. /dev/hdX) in cahoots

When experimenting with recovery scenarios using USB flash drives in a hub
I expect that I encounter "mystery" that doesn't fairly represent IDE type
drives. Hmm on that thought I wonder if it fairly represents a SCSI type array....Naw... USB flash drives are silly fun. What I have seen so far is that the mappings I am working with from the grub command line are different betweeb rescue mode on a particular distribution CD from what I see at the grub command prompt during a boot from a fresh install from the CD distribution from which that rescue boot came. I think this is without changing physical "drive" configuration. I probably just screwed
something up .... This will require further observations.

I am not ready to start messing around with this on my server class systems
anticipating that it will open up a new can of worms with system specific configuration utilities ... but perhaps the SCSI IDs will help bring some sanity... Normally I use hardware RAID, but given how low end my controllers are it might be worthwhile to compare the hardware and software based solutions...


-Mike