Re: [gentoo-user] LVM for data drives but not the OS

[Dale]

Joost Roeleveld wrote:
> On Thursday 07 April 2011 08:57:40 Dale wrote:
>
>> Neil Bothwick wrote:
>>
>>> On Thu, 07 Apr 2011 15:21:33 +0200, Joost Roeleveld wrote:
>>>
>>>> I think Dale will probably succeed in breaking it :)
>>>>
>>>> Dale, this comment isn't meant as an insult. I honestly think you
>>>> would
>>>> be perfect for some QA or Testing job :)
>>>>
>>> But not on any project you wanted to finish on time ;-)
>>>
>> Joost, I see your point.  This is my life saying.  If it wasn't for bad
>> luck, I wouldn't have any luck at all.  I hope for the best but expect
>> the worst.  You should see my dining room.  Full of food stuff just in
>> case.  After my last visit to the grocery store, I'm thinking I may not
>> have enough yet.  o_O  I also have a generator and some gas stored too.
>> I also have a big garden to grow food as well.  I may be disabled but I
>> ain't stupid.  I just try to keep the bad things that can happen in the
>> back of my mind and keep a plan going, just in case it does hit the fan.
>>
> The Internet is a mixed blessing. We only see what people type. But have
> difficulty understanding their personal situation because we don't see it.
> Up untill the point you mentioned you're disabled, I was like "Hmm... I know a
> few people like that :) "
> I would call that self-sufficient and quite clever. I would like to be able to
> move somewhere where I could just enjoy life and life of some piece of land.
>
> I would not consider you stupid, you've shown, at least in my opinion, that
> you're not :)
>
>
>> I'm sort of wanting to use this as a learning experience.  If I can get
>> things set up, working and understand what the heck things do, then I
>> may try some more stuff.  Right now, my light bulb is pretty dim on
>> LVM.  I don't understand how it works and what the heck those commands
>> do.  I'll have my light bulb moment eventually.  Since I don't have the
>> new drive ordered yet, I got time to read, listen and try to grasp it all.
>>
> The beginning of wisdom is admitting you don't have it ;)
>
>
>> Just a old dog trying to learn new tricks.  lol
>>
> I'm lousy at training dogs (or other animals), but lets see if I can make LVM,
> or at least the way I use it, a bit clearer.
> If anything isn't clear, please ask.
>
> We've already discussed the benefits of using it in a previous thread. So I'll
> just skip those for now.
>
> With LVM, you end up with 1 or more VGs (Volume Group)
> Each VG consists of 1 or more PV (Physical Volume)
> Each VG can contain 1 or more LV (Logical Volume)
>
> In simple graphic:
> PV<->  VG<->  LV
>
> A PV is either an entire physical disk or a partition on a physical disk. This
> is why they're called "Physical Volume"
>
> A VG is a collection of Physical Volumes. The size of this depends equals the
> total size of all the PVs in this group.
>
> An LV is a partition on this Volume Group.
>
> Now, here comes the nice part. It is possible to extend a VG and LV.
> A VG is extended by adding a PV. It can also be reduced in size by removing a
> PV.
> NOTE: when removing a PV, ensure it is not used. (Tools exist for this)
>
> An LV can be extended as long as the VG has room for this. No movement of LVs
> is necessary, just like files on a filesystem, they get spread over available
> space.
> NOTE: Yes, this does lead to fragmentation (Tools exist to assist in
> defragmenting LVM)
> You can also reduce the size of an LV. (Again, make sure reducing the LV in
> size does not lead to loss of data)
>
> On top of an LV, any filesystem (Ext2/3/4, Reiserfs, XFS, JFS,....) can be
> placed. Once an LV is created, the filesystem tools can simply access it just
> like any other block device (eg. physical disk)
>
> When selecting a filesystem to put on top of an LV, do check wether or not it
> at least supports increasing the size after creation. Most filesystems in use
> do support this even while the filesystem is mounted.
> Reducing the size of the filesystem is, in my use, less common. And I tend to
> simply copy data to a temporary location when I do need to reduce the size.
>
> I hope the above makes it a bit clearer on how it "works".
>
> The actual commands for creating and managing an LVM-system, I'll leave for
> another time if and when they are needed.
>
> --
> Joost
>
>

I'm going to give this a stab here.  I go buy a new drive. I use cfdisk 
to make it ready for LVM, the 8E thingy.  I then tell LVM to make it a 
Physical Volume, either in whole or in part.  I then tell LVM to make it 
a Volume Group and if I already had a drive using LVM I could then add 
the new drive to it.  After that, I create Logical Volumes and put file 
systems on it for use sort of like the old partitions.

Am I sort of getting on the right track?

Did someone mention a GUI for this?   ^-^

Dale

:-)  :-)