[gentoo-user] Re: Re: OT: Is EVMS dead?

[Alexander Skwar]

Eric S. Johansson <esj@××××××.org> wrote:
> Alexander Skwar wrote:
>> Eric S. Johansson <esj@××××××.org> wrote:
>>> Dirk Heinrichs wrote:

>> pvcreate /dev/hda vgcreate data /dev/hda lvcreate -L42g data mkfs
>> /dev/data/lvol0
>>
>> What's so hard about that? Does that fit on a postcard?
>
>   it needs a little more detail so a user can extrapolate to what they
>   need but,

The detail can be found in the howto; eg. http://tldp.org/HOWTO/LVM-HOWTO/index.html

> What is hard however is developing the postcard level documentation for
> disaster
> recovery.

- Get new drive
- Do as mentioned above
- Get stuff from backup

Pretty short, if you ask me ;)

>> -v: pvcreate /dev/hda: Intialize the device as a physical volume (pv), so
>> that it can be used by LVM. One time job.
>
> would need reference physical volume, physical device associations (i.e.
> single
> disc or hardware raid).

What?

> is there any way to display/enumerate them
> independent
> of non-LVM devices?

Pardon?

>> vgcreate data /dev/hda: Create a container called "data" which will hold
>> the different sub-containers. The "data" container is made up of the
>> /dev/hda physical volume.
>
> what is a sub container?

Exactly.

> why is it needed? when do you need it?

That's too basic. People asking that kind of question shouldn't be
administering a system.

> do/can
> you
> create a container spanning multiple devices?  When, how, why?

See howto.

>> lvcreate -L42g data: Create a logical volume (lv) on the "data" volume
>> group (vg). It's sized "42g" (42GiB).
>
> again, is a logical volume a single physical volume?

They don't belong together. See the howto.

> If the volume group
> called data (how did it get from container to volume group)

What?

> is the same as
> the physical volume,

It isn't. As explained in the howto.

> why not just use the physical volume?

What?

>> mkfs /dev/data/lvol0: Create a file system on the newly created lv.
>
> in other words, the logical volume is  treated by the system in exactly
> the same
> way as a physical volume.

Nope.

> It's a logical disk.

What?

> these are just some of the "naïve user" questions that come to mind.

Those users shouldn't admin a system.

> They
> aren't answers concisely in most of the documentation I have seen.  Part
> of the reason I say "explain it on a postcard" is because the format
> forces you to
> focus your thoughts and explain the system concisely.

And those useless questions are because you wanted a postcard explanation.

>>> with your users or the implementation is really off.
>>
>> Nope. Some things simply *ARE* complicated.
>
> Richard Feynman, a great physicist, once stated that if you can not
> explain a (physics) problem at a freshman level then you don't understand
> the problem.

Might be. But you need to have more space than a postcard.

> Edward Tufte has a series of books on information design
> simplifying
> complicated things so that you can communicate clearly.  Either of these
> men are
> smarter than you and I put together.

That's not hard (well, at least as far as being smarter than me is
concerned *G*).

Alexander Skwar

-- 
gentoo-user@g.o mailing list