Re: [gentoo-user] LVM (Was: the best filesystem for server: XFS or JFS (or?))

[Mark Knecht]

On Sat, Mar 26, 2011 at 3:20 PM, Dale <rdalek1967@×××××.com> wrote:
> Alan McKinnon wrote:
>>
>> On Saturday 26 March 2011 15:06:31 Elaine C. Sharpe wrote:
>>
>>>>
>>>> Just because something works for most people, doesn't mean it will for
>>>> everyone either.  If you lose data, it doesn't matter.  LVM just adds
>>>> one more layer of something to go wrong.  Me, I don't need the extra
>>>> risk of having a system that doesn't boot and a loss of data.  I'm sure
>>>> there are a lot of people that see it the way I do too.  They just
>>>> don't
>>>> need the extra risk.
>>>>
>>>
>>> Using the least number of layers of abstraction you can get away with is
>>> a perfectly valid criteria. What I was pointing out was that informal
>>> polls of users with a sad story to tell is not a very effective way to
>>> conduct research. People say all kinds of things that just aren't true.
>>>
>>
>> There's an elephant in this room. The number of actual layers is greater
>> than
>> just LVM plus FS. It's whatever the BIOS (or a reasonable substitute is
>> doing), plus the drive firmware, kernel driver(s) - there's more than one
>> of
>> those - plus any RAID in use (hardware or software) and finally the file
>> system.
>>
>> That's a lot of layers, a lot of code, a lot of opportunity for people to
>> reveal the extent of their lack of knowledge. I've often heard it said
>> that
>> code like ZFS and brtfs eliminates several of these layers therefore it's
>> technically a better option. That may be true, but let me just point out
>> that
>> whatever LVM+fs+other_stuff is doing as separate chunks of code also gets
>> done
>> by ZFS etc. You just don't see it, and just because it's abstracted away
>> doesn't mean it's not there.
>>
>>
>
> I'll add this.  Alan if I recall correctly runs a lot of systems.  He has a
> boatload of experience using all sorts of software/hardware.  Me, I don't.
>  For the longest, I had one system and that was it.  If I upgrade my kernel,
> LVM, or some package that LVM depends on and I can't boot, I'm screwed.  If
> I can't boot, I can't google anything to find out how to fix it.  I also
> don't know enough about LVM to fix it myself.  Since there is so many layers
> of things that can already go wrong on a system, adding one more layer that
> can be complicated only makes a problem grow.
>
> I'm sure Alan and many others could go out and buy or build a new system and
> put LVM on it and fix about any problem that comes along.  Thing is, there
> are others that can't.  Add to this that when I was thinking about using it,
> I read where a lot of people, for whatever reason, couldn't get it back
> working again and lost data.  For me, I don't care if it was LVM itself, the
> kernel or some combination of other things, if I can't boot or lose data,
> the result is the same.  I can fix a kernel problem, a broken package but if
> LVM fails, I'm stuck.
>
> That said, I now have a second rig.  I may at some point use LVM because I
> can always go to the other room and use my old rig to get help.  I already
> have a 750Gb drive that is about full of pictures, I got a camera and get a
> little happy at times, and videos I have downloaded, everything from TV
> series to stuff off youtube.  I may buy another large drive and use LVM or
> something to give me more room since I really don't want to have to break up
> my filing system across two separate drives.  I won't consider putting the
> booting part of my OS on LVM tho.
>
> Of course, I did see a 3Tb drive on sale the other day at newegg.  o_O  That
> would last a while.  ;-)
>
> Dale
>
> :-)  :-)

Dale,
   I understand your position and concerns. While I have a number of
systems, I have little time or patience for dealing with a lot of this
stuff and LVM has been one of them.

   One thing I'm considering to try out LVM is a second Gentoo
installation on an already running system. It will either be a 50GB
partition of its own, or a Virtualbox VM. I'd do the normal Gentoo
install for LVM, figure out how it works, etc., and then decide if I
want to use it in the future.

   After all, as Neil said, if something offers features we don't feel
we need then why buy it?

- Mark