Re: Root on RAID
On Fri, 3 Aug 2001 06:19, Brian May wrote:
> Alvin> hi ya george
>
> Alvin> for raid1.... typically /dev/hda is copied to /dev/hdb
>
> Alvin> - dont know why you'd wanna mirror a partition... (
> Alvin> system will still be dead since the rest of the required (
> Alvin> partition is not available
>
> Easy, you create a separate software-RAID1 partition for every
> partition on you harddisk, so in affect you mirror one harddisk on to
> the other harddisk.
>
> It might be possible (?) to mirror /dev/hda to /dev/hdb, but then you
> need to subdivide that space up into partitions.
Sure, it's quite possible to mirror /dev/hda to /dev/hdb, but then the
auto-detect RAID stuff (which relies on having partition type 0xfd) won't
work. But then it won't work with RAID in a module on an initrd either - and
with the modern setup this is what you should be doing.
> lvm could be used to do this (AFAIK), but all my attempts to use lvm
> up to now have failed.
Yes. Ideally you mirror the raw devices (if the sizes match) and then run
LVM on that. For different size disks you have to mirror a whole disk to a
partition on the larger disk, but such mirroring won't give best performance
either...
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