Most of your questions are probably answered by
"man lvm". The "lvm" command also goes by other names,
each with their own man page, and you'll probably want
to start with the tools to scan for LVM "things":
pvscan
vgscan
lvscan
Why don't fdisk& parted support it properly yet?
The same reason that screwdrivers don't know
anything about televisions. Screwdrivers are for
screws. Televisions may have screws as one of their
parts, just as partitions may be used to build physical
volumes, but the partition tools only care about the
partitions, not what you might be building from them.
Generally, physical volumes go on partitions, volume
groups go on partitions, and logical volumes go on volume
groups. So a logical volume is three steps removed from
a partition, maybe four if RAID is included. Is it confusing -
yeah, a little bit at first, but the same indirection that
makes it a little complicated makes it SUPER flexible.
Some people actually partition their logical volumes,
putting what I consider to be the "bottom" level on
top. I normally do RAID on the bottom, then partitions,
then physical volumes, but I've seen people mix up
the order in all sorts of ways for their specific needs.
--
Ray Morris
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On 05/15/2010 11:16:42 PM, kanonmatswe wrote:
On 05/15/2010 01:17 AM, giovanni_re wrote:
I got no answer on the Ubuntu list, so trying here.
==
KU 10.4. Desktop with2 hdisks. 1.5TB has 9.04, was hda/sda. Now
install
a 2TB as sda, move old disk to sdb.
Alternate install 10.4 on the 2TB sda. Grub finds the 9.04 install
on
sdb,& installs fine on sda.
Both installs have a /home partition in their sda4 logical partition,
probably sda5 on each drive when they were installed.
10.4 boots fine on the 2tb, but 9.4 refuses to boot off now sdb.
Less important question: Suggestions for getting the 9.4 to boot
when
that drive has been moved from sda to sdb (data connector on the
motherboard). It's probably a mount issue?
== How does one see the logical partitions??
fdisk -l,& parted -l,& gparted, I have used - a few days ago, so I
don't recall the specifics right now.
IIRC, on 9.04 as sda, gparted would see the LVs,& show some info
about
them.
When I boot 10.4, IIRC gparted doesn't pull up any info about the
LV's,
even on the sda drive with the 10.4 os it booted from. :(
IIRC, none of those programs show info about the LV's on sdb, which
has
the 9.4 install on it.
So, is LVM properly supported in some partition creation/diagnostic
sw??? ex: fdisk, parted, gparted? Is there some other program that
will
at least see,& perhaps show some info about those partitions?
How about creating more LVs in the free space on the drives? What sw
can do that from the running 10.4 system? (ie, I don't want to have
to
use the alternate installer disk to do partitioning, now that the os
is
installed. I'm hoping that is possible - hasn't LVM been out for
quite
a while? Why don't fdisk& parted support it properly yet? BTW,
what
orgs create& support the LVM sw? GNU? Linux Kernel?? Other?
==
Most Important: How can I get 10.4 to be able to see& mount the 9.4
/home partition which is now on (probably) sdb5? What info will be
needed by the mount command? UDEV #? What sw (parted, fdisk,???)
will
show the info necessary to use in the mount commnad??
==
Refs:
http://en.wikipedia.org/wiki/Logical_Volume_Manager_%28Linux%29
http://sourceware.org/lvm2/
http://sunoano.name/ws/lvm.html
https://www.redhat.com/mailman/listinfo/linux-lvm
==
Any other suggestions about mail lists or places to get other
informed
answers about this?
Thanks for all thoughts/suggestions. :)
_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
Logical partitions don't have much to do with lvm, which is a layer
above disk partitions. Maybe you mean "logical volumes"? To see what
you can do with lvm: "man lvm" if you have the lvm2 pkg installed.
Have you read the howto?http://tldp.org/HOWTO/LVM-HOWTO/ After a
read, I suggest "modprobe dm_mod" to load the necessary module into
the kernel and "vgchange -ay", then see what lvm stuff you have with
"pvdisplay", "vgdisplay" and "lvdisplay". I think there might be a
lvm2 init script, but I don't know where ubuntu places those. This
may be offtopic, but you can use labels or UUIDs (for example in grub
and fstab) to keep track of partitions. My logical volumes have
UUIDs, but I usually mount them with the "mapper" path. Something
like: /dev/mapper/<VOLUMEGROUP>/<VOLUMENAME>
_______________________________________________
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linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
_______________________________________________
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https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
