[CentOS] When should LVM be used?

[Rudi Ahlers]

On Mon, Aug 9, 2010 at 11:00 AM, Ron Blizzard <rb4centos at gmail.com> wrote:

> On Sat, Jul 31, 2010 at 8:52 AM, Drew <drew.kay at gmail.com> wrote:
>
> > LVM adds flexability that regular partitioning can't.
> >
> > Example 1. Say you've mounted an entire 2TB disk as /home and it's
> > almost full. Now you want to add another 2TB to /home. How do you?
> > Easiest way is with LVM. You just add the new disk into LVM's pool of
> > storage and expand the home partition (Logical volume) to use the new
> > space. Now you have a single filesystem spread across two disks.
> >
> > Example 2. Now let's say that you bought a NAS device (QNAP, Drobo,
> > Buffalo) that does iSCSI or NFS and you want to move your data off the
> > two local disks. With LVM you just add the new 'disk' into the pool
> > then tell LVM to move existing data off the 'old' disk.
> >
> > Try doing that with parted. :-P
>
> I understand the advantages when using a server, but my personal
> computer is a Small Form Factor Dell GX270 with only one hard drive
> slot.  But I'll look closer into LVM options when I install on the
> bigger hard drive. Thanks.
>
> --
> RonB -- Using CentOS 5.5
> _______________________________________________
>
>
>

Even in this case, LVM could be useful. In general, you don't want to put
everything in on large partition. What do you do with 1TB's worth of data
when you decide to upgrade CentOS 4 to 5 (as an example) or install Ubuntu?
With LVM, you simply create a 900MB LVM volume for your data and reinstall
the OS :)

BUT, let's say you decide to allocate 10GB to /, 4GB to swap & 1GB to /tmp.
Suddenly your / partition is full and you can't install more stuff. With LVM
you can quickly shrink /home and increase the size of /. All on the go
without having to reboot. I found this very handy while working on a Windows
VM installed on my home PC, which was busy doing some video rendering and I
didn't want to stop the rendering to increse the / partition.


>
> --
> Kind Regards
> Rudi Ahlers
> SoftDux
>
> Website: http://www.SoftDux.com
> Technical Blog: http://Blog.SoftDux.com
> Office: 087 805 9573
> Cell: 082 554 7532
>
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