> Michael Franzino wrote:
>
>I'm new to Linux and this discussion group so
>please be patient.
I'm fairly new to this group, also, but I have had
considerable experience with RAID 1 on Sun OS
& Solaris.
> . . . It is the three
>SCSI drives that make up the mirrored pair
>plus one spare. I want to use cron to bring-down
>one of the drives in the mirrored pair every hour.
>The reconstruction will then bring in the spare as
>the new half of the mirrored pair. The idea (likely
>bad) is that this makes sure I always have a good
>filesystem no more than one hour old on the drive that
>has been brought down? To make this work I need help
>with following questions:
>
If it were my system, I would prefer to have a three way mirror
with at least two (ideally, three) separate controllers.
I would want to detach a mirror to backup the system to tape,
daily, giving me a snapshot of the system. If I were really
paranoid, I would detach and reattach this mirror several times
a day for backup. This would make a less vulnerable
system and the type of data security you are looking for.
Reconstructing as you suggest leaves you with one drive on line,
one rebuilding and one with data that is growing stale as you reconstruct
the new one. The whole point of RAID 1 is to have redundant data
storage.
If you detached to backup the system, you would still have your
questions:
>1) Once a spare has become part of the mirrored
> pair (after reconstruction), how do I re-introduce
> the third drive back as the new spare? Are there
> console commands for this?
This would change to how do I detach and reattach a sub mirror.
Bob Gerrish
