[CentOS] Some basic LVM questions

Sun Nov 8 12:13:53 UTC 2009
M. Hamzah Khan <hamzah at hamzahkhan.com>

On Sat, 2009-11-07 at 22:22 -0800, Monte Milanuk wrote:
> Hello all,
> 
> I've been 'away' from all things Linux in general and RH in particular
> for a long while, so I've got some catching up to do ;)
> 
> I've got a pretty fair collection of tabs reading on LVM and how it
> works and why its such a great thing for enterprise use, etc., being
> able to add storage to the pool and all that.  LVM was just kind of
> catching on when I moved away from Linux for a while, so it's a little
> odd to me.  
> 
> What I have currently is an older PC that I'm hoping to use as a home
> server / occasional 'workstation'.  One 13GB main drive, and a 500GB
> drive for network storage.  The default install in CentOS 5.4 seems to
> want to just lump everything together in one big volume.  I was
> thinking perhaps it'd be better to have two volumes (or pools, like I
> said - still learning and not entirely confident of the lingo
> involved)... one for the main or 'system' drive (the 13GB one with /
> mounted on it), and another one for the 500GB sata drive on it - so if
> I want to add another big drive for more storage, it'd go under that
> group, ready to serve up storage to the WLAN.
> 
> Is there anything particularly 'wrong' with that layout, as compared
> to the default 'everything in one logical volume' approach that the
> installer utilized?

There won't be any issue in doing this. The installer just tries to make
things easier by creating one big volume group.

I'd say that in some ways seperating the two disks in this case would
actually be better. :)

With both drives in one big volume group, failure of one drive will
(most likely) cause both the OS and data to be lost. 

Seperating them will mean that if your OS drive fails you can replace
the dead drive, reinstall CentOS (or restore from a backup), and your
data will be accessible again.

Of course you would still have to create regular backups, or you would
still be in a very unhappy situation if the data drive fails but it
would still save you a lot of headache in the event that you encounter a
situation in which only the OS drive fails. :)

Regards

Hamzah

-- 
M. Hamzah Khan
RedHat Certified Engineer Number: 804005539516829
Email: hamzah at hamzahkhan.com
URL: http://www.hamzahkhan.com
Mobile: +44 (0)7525663951
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