[linux-lvm] my project

[Afonso Henriques Silva Leite]

Hi everybody!!
First of all, I would like to apologize if my inexperience causes any
inconvenience.
I was reading lvm howto, and in the 5.7 section there was a suggestion
do discuss my ideas on the developer list, so here I am.
My project is to create a lvgroup to enlarge my root partition, so that
I can install Sage and Mathematica on it.
I divided my only 40GB hard disk as follows:

Comando (m para ajuda): p

Disco /dev/sda: 40.1 GB, 40060403712 bytes
255 heads, 63 sectors/track, 4870 cylinders
Unidades = cilindros de 16065 * 512 = 8225280 bytes
Identificador do disco: 0xea84ea84

Dispositivo Boot Início Fim Blocos Id Sistema
/dev/sda1   *           1         623     5004216    7  HPFS ou NTFS
/dev/sda2             624        4870    34114027+   5  Estendida
/dev/sda5            4689        4870     1461883+  82  Linux swap /
Solaris
/dev/sda6             624        1246     5004184+  83  Linux
/dev/sda7            1247        4688    27647833+  83  Linux

My idea was to have a big partition only for documents, and a lower one
just for distro installations, so that I wouldn't need to do backups
when I decided to change the distributions. But after a few weeks, the
root partition was almost fullfilled, as df -H shows:

Sist. Arq.             Tam    Usado Disp  Uso% Montado em
/dev/sda6              5,1G   4,1G   738M  85% /
udev                   257M   283k   257M   1% /dev
none                   257M   873k   256M   1% /dev/shm
none                   257M    87k   257M   1% /var/run
none                   257M      0   257M   0% /var/lock
none                   257M      0   257M   0% /lib/init/rw
none                   5,1G   4,1G   738M
85% /var/lib/ureadahead/debugfs
/dev/sda7               28G    17G   9,8G
63% /media/04d003f6-a6ee-4a6c-8c84-2dd1136f8242

So guys, what do you think? Can I solve my problem with lvm? I mean, I
remember reading a warning to do not use lvm with root partitions. It's
impossible to do it?

Again, sorry for my poor english and inexperience, and thanks anyway.