[Gllug] RAID on RAID

[Rich Walker]

Since the list is quiet...

I was pondering disk allocation strategies the other afternoon, and I
suddenly realised I've allocated my root partition all wrong on the
server...

At the moment, the root partition is the only un-raided partition. There
are 4 disks, on separate cables, with a bunch of partitions doing a
bunch of stuff.

The idea that occurred to me was to allocate a ~5GB chunk of each disk
and then do 
hda1 + hde1 => md0, RAID1
hdc1 + hdg1 => md1, RAID1
md0 + md1 => md2, RAID1

and then mount md2 as /

Now, clearly write will be slow :-> But write to / is rare - most writes
go to /home, /var, /tmp and some to /big.

Reads should alternate between md0 and md1.

If any one disk controller goes down, no problem.
If any three disks go down, no problem.

But will LILO or GRUB cope with booting from RAID-on-RAID? And have I
missed anything?

cheers, Rich.

-- 
rich walker         |  Shadow Robot Company | rw at shadow.org.uk
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