LVM and RAID

[Roger Oberholtzer]

On Thu, 2005-06-16 at 16:16, Mike Reinehr wrote:
> On Thursday 16 June 2005 02:10 am, Roger Oberholtzer wrote:
> > I have just been playing with Linux LVM and am quite impressed. It seems
> > too simple. At least when set up from SUSE 9.2. I have a few questions
> > for anyone who has worked with this:
> >
> > 1. Are there any gotchas when using a LVM on different distros? Aside
> > from the fact that the config may be different? Anything in the LVM
> > itself? If I set up a LVM on, say, SUSE, and later move to something
> > else (I am not considering this - but I want to know), could I expect
> > difficulties?
> >
> > 2. Can I set up a LVM that is also RAID? That is, having a file system
> > with oodles of storage is fine, but what about failure protection?
> 
> Roger,
> 
> 	LVM on top of RAID works like a charm. What I have gotten from other lists, 
> and agree with, is to define three md RAID partitions:
> 
> 	/dev/md0	RAID1	/boot	ext2	(using /dev/sda1 & /dev/sdb1)
> 	/dev/md1	RAID1	/		ext3	(using /dev/sda2 & /dev/sdb2)
> 	/dev/md2	RAID1	LVM PV	---		(using /dev/sda3 & /dev/sdb3)
> 
> uses sizes you feel adequate for / & /boot & then use all the rest for md2, 
> with one VG on the single PV. Then divide up your VG with any all remaining 
> file systems (swap, /home, /var, /usr, etc.), as you please. Remember to set 
> the partition (/dev/sda... ) types as Linux RAID, so they will be 
> auto-detected at boot and don't forget to include md support & device mapper 
> support in your kernel.

Wow.

When I make the partition for use with LVM, I set the partition to Linux
LVM, and tools look for these partition types when I make the VG. But if
I build this on top of RAID, the partition will be Linux RAID instead?

I need to draw a map of the layers so I can see what each one expects.

But I see that I (obviously) need to get RAID working first.

+????????????????????????????+???????????????????????????????+
? Roger Oberholtzer          ?   E-mail: roger at opq.se        ?
? OPQ Systems AB             ?      WWW: http://www.opq.se/  ?
? Kapellgr?nd 7              ?                               ?
? P. O. Box 4205             ?    Phone: Int + 46 8   314223 ?
? 102 65 Stockholm           ?   Mobile: Int + 46 733 621657 ?
? Sweden                     ?      Fax: Int + 46 8   314223 ?
+????????????????????????????+???????????????????????????????+