Re: [gentoo-user] Mounting Question...

[Mick]

On Friday 21 December 2007, Benjamen R. Meyer wrote:
> Galevsky wrote:
> > On Dec 20, 2007 10:31 PM, Mick <michaelkintzios@×××××.com> wrote:
> >> Unlike commonly perceived wisdom I don't think that LVM is a panacea for
> >> all ills, or a necessity as such.  It is however bloody convenient,
> >> especially on a growing fs.  A server that is not expected to change
> >> much in size, probably does not need it.  On the other hand some servers
> >> (file, mail, news servers) are bound to continue to accumulate data and
> >> their fs will increase in time. I would argue that the former type of
> >> server can happily live in a few primary partitions + 1 extended with a
> >> number of logical partitions, if you are going for a multi-partitioned
> >> scheme, while the latter type of server will greatly benefit from LVM.
> >> Of course, if hard drive redundancy is necessary, then I can't see how
> >> you could live without LVM + RAID.
> >
> > I understand you on "LVM is not a must for very stable servers", but
> > since I can't see any good reason not to use LVM,  I see no reason to
> > limit your abilities to extended partitions. We have the opportunity
> > to be more flexible with LVM, why should we not get it ? To loose the
> > ability to extend a partition by adding a new HD without any pain ? I
> > mean, if you don't know how to use it, I understand that you may skip
> > installing a LVM system, but when you did it once, I see no reason to
> > install your new systems without. So, I am interested in your advice
> > about LVM is not the universal solution for partitions management,
> > since I am sure I have something to learn from you experience.
>
> Agreed. As I said in another e-mail on the list, I use to use extended
> partitions - at one point I had about 10 or so partitions on a single
> drive (3 primary, the rest from an extended partition). This worked well
> under Windows 9x, but was a pain after moving to Linux. It wasn't that I
> had mis-scoped the size of the data for those partitions, just that my
> needs changed (mainly user related needs, not system related needs), and
> managing extended partitions is a lot of work. I very much understand
> LVM and what would do for me, and would very much like to hear why
> simple extended partitions would be better for any scenario but the most
> limited of scenarios where LVM was just not possible (e.g. the system
> could not run a kernel that supported LVM; or RAM on the system was too
> limited to support running LVM; etc.)...I'm not sure I agree that they
> would be.

Guys, mine is not any precious experience that you could learn much from (I am 
sure others on this list have more valuable experience on this matter), but 
what I am saying is this:

If you have a stable, dedicated server which is NOT going to increase in fs 
size requirements, then a conventional non-LVM installation will do exactly 
what you need done, in a simpler fashion.  To define "simpler" in a server 
use case, I would say that anything that you do not absolutely need should 
not be installed (for basic security and maintainability reasons), including 
LVM kernel modules and what not.  On the other hand, installing and 
maintaining an LVM based fs is clearly not difficult and if you are uncertain 
about your current/future fs size requirements, then you're better off 
installing LVM and making use of the flexibility it offers.

BTW, if you're thinking of the flexibility of adding drives/partitions and 
extending LVG's at will, you should also consider that unless you're running 
a mirror RAID when any-one of your drives goes bang! you will lose all your 
VG data irrespective on which drive (PV) they reside.  Of course, you know 
this and you keep recent back ups of your data at all times, right?  ;-)

I can recall at least 4 server installations where I did not run LVM and I 
never had to increase the fs size (one of them has been running for more than 
3 years now and it fs is spread over two drives).  On the other hand a server 
I built less than two months ago has LVM and all data (but not its / ) is 
stored in LVs.  I already had to replace a drive on that machine which was 
suspect for an imminent failure.  A case of "horses for courses".

Just my 2c's.
-- 
Regards,
Mick