Logical Volume Manager

# file --special-files /dev/mapper/datavg-nom_lv
/dev/mapper/datavg-nom_lv: Linux rev 1.0 ext2 filesystem data (mounted or unclean)

ANTECEDENTES

Tenemos un disco duro con dos particiones:

/dev/sda1 ⇒ /boot /dev/sda5 ⇒ extendida LVM

Hemos trasteado el LVM y no arranca. Para montar LVM desde una live-cd:

1. Arrancar desde la live-cd

2. Buscar el VG:

vgscan

3. Activar el VG:

vgchange -a y vg_encontrado_paso_2

4. Montar el LV en cuestión, en mi caso el raíz:

4.1 mkdir /mnt/auxiliar

4.2 mount /dev/mapper/vg_encontrado_paso_2-root /mnt/auxiliar

https://www.redhat.com/archives/linux-lvm/2006-August/msg00081.html

ANTECEDENTES

Tenemos un VG (Grupo de Volúmenes) con 3 LV (Volumen Lógico):

/
/home
/swap

Queremos achicar el LV /home para dejar espacio con el objeto de crear en ese espacio liberado un cuarto LV, donde montar /var

1. (Todo como root) obtenemos información del VG:

clear && lvdisplay

--- Logical volume ---
LV Name                /dev/volumen/root
VG Name                volumen
LV UUID                ErCMtp-5H0L-cUv9-AS7L-B1Gq-9fuM-xFtcDN
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                6,68 GB
Current LE             1709
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:0
 
--- Logical volume ---
LV Name                /dev/volumen/swap_1
VG Name                volumen
LV UUID                ly0S8s-MC2A-31yG-1dba-NYZk-ohQ0-yg1o6l
LV Write Access        read/write
LV Status              available
# open                 2
LV Size                2,59 GB
Current LE             664
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:1
 
--- Logical volume ---
LV Name                /dev/volumen/home
VG Name                volumen
LV UUID                uQkCYh-3u1z-s6yq-0dpA-Q6MK-5PIO-7zAoy9
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                65,00 GB
Current LE             16639
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:2

2. Desmontar la partición (por si las moscas, pero creo que desde el kernel 2.6 con sistemas de ficheros EXT3 NO es necesario). Es mejor si salimos del entorno gráfico:

umount /dev/mapper/volumen-home

3. Entrar en la consola de lvm y realizar unas operaciones:

3.1 lvm 3.2 Buscamos VG:

vgscan

3.3 Activamos el VG:

vgchange -a y VolGroup00

3.4 Generamos los ficheros de dispositivos ¿?:

vgmknodes

3.5 Salimos de la consola lvm:

exit

4. Achicar el sistema de ficheros

4.1 Comprobar el sistema de ficheros del LV:

e2fsck -f /dev/mapper/volumen-home

4.2 Redimensionar la partición ¿? (por ejemplo a 35 Gigas):

resize2fs /dev/mapper/volumen-home 35G

5. Achicar el LV:

5.1 Entrar en la consola lvm:

lvm

5.2 Reducir el LV (NOTA: según el tutorial la ruta es distinta, pero a mí tras avisarme que se podían perder datos me funcionó):

lvreduce -L36G /dev/volumen/home

O:

lvextend -L36G /dev/volumen/home

Creo que tanto da que da lo mismo

5.3 Salir de la consola:

exit

6. Expandir el sistema de ficheros al tamaño total del volumen.

resize2fs /dev/mapper/volumen-home

A mi me dijo que no se hacia nada

7. Aqui se puede volver a montar el sismte a de ficheros y ver los cambios. Más simple reiniciar

lvreduce -L19G /dev/mapper/fixe-home

fixe:/home/jose/Desktop/Downloads# lvdisplay 
  --- Logical volume ---
  LV Name                /dev/fixe/root
  VG Name                fixe
  LV UUID                pi5FAr-znWl-Wkma-a5FB-Lvku-Mmv3-e1vcJO
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                332.00 MB
  Current LE             83
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:0
   
  --- Logical volume ---
  LV Name                /dev/fixe/usr
  VG Name                fixe
  LV UUID                AHwTdB-ev37-LmDi-4ldW-k0fT-GD3Z-ajzZjl
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                4.66 GB
  Current LE             1192
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:1
   
  --- Logical volume ---
  LV Name                /dev/fixe/var
  VG Name                fixe
  LV UUID                41g0b1-YrLd-cHte-AoOT-Wtuz-4OSy-B59aJl
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                2.79 GB
  Current LE             715
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:2
   
  --- Logical volume ---
  LV Name                /dev/fixe/swap_1
  VG Name                fixe
  LV UUID                ndI2u3-Si6h-tB1U-lLoB-b7o6-cjQt-pIGoAH
  LV Write Access        read/write
  LV Status              available
  # open                 2
  LV Size                3.84 GB
  Current LE             983
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:3
   
  --- Logical volume ---
  LV Name                /dev/fixe/tmp
  VG Name                fixe
  LV UUID                PuyyLe-lwAF-xsK3-XSbX-UabV-YKea-ZUnLl4
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                380.00 MB
  Current LE             95
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:4
   
  --- Logical volume ---
  LV Name                /dev/fixe/home
  VG Name                fixe
  LV UUID                DTGGm1-lOem-0po1-BApp-ave5-wh2p-qLWCVk
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                19.00 GB
  Current LE             4864
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:5

lvreduce -L19G /dev/mapper/fixe-home

  WARNING: Reducing active and open logical volume to 19.00 GB
  THIS MAY DESTROY YOUR DATA (filesystem etc.)
Do you really want to reduce home? [y/n]: y
  Reducing logical volume home to 19.00 GB
  Logical volume home successfully resized

lvextend -L1G /dev/mapper/fixe-root

  Extending logical volume root to 1.00 GB
  Logical volume root successfully resized

resize2fs /dev/mapper/fixe-root

resize2fs 1.41.3 (12-Oct-2008)
Filesystem at /dev/mapper/fixe-root is mounted on /; on-line resizing required
old desc_blocks = 2, new_desc_blocks = 4
Performing an on-line resize of /dev/mapper/fixe-root to 1048576 (1k) blocks.
The filesystem on /dev/mapper/fixe-root is now 1048576 blocks long.

resize2fs /dev/mapper/fixe-home 

resize2fs 1.41.3 (12-Oct-2008)
Filesystem at /dev/mapper/fixe-home is mounted on /home; on-line resizing required
On-line shrinking from 6564864 to 4980736 not supported.

Tenemos 80 Gb en home y queremos pasar 20 a una unidad de apoyo

Reducimos tamaño del primer LV:

lvreduce -L60G /dev/mapper/vol64-64_home 

Creamos el LV de apoyo:

lvcreate vol64 --name apoyo --size=20G

Formatemos el LV:

mkfs.ext3 /dev/mapper/vol64-apoyo

Ya está listo para montar

(Creo que todo como root)

1. Obtenemos el nombre del Grupo de Volúmenes

calero:~# vgscan
Reading all physical volumes.  This may take a while...
Found volume group "calero" using metadata type lvm2

2. Renombramos:

vgrename calero nuevo_nombre_vg

(Creo que todo como root)

1. Obtenemos el nombre de todos los Volúmenes Lógicos del Grupo de Volúmenes:

calero:~# clear && lvdisplay 

1. – Logical volume —

LV Name /dev/calero/root

VG Name                calero
LV UUID                KopwfX-2SZG-JJNg-H0xs-6dnb-zwmB-zBUMZR
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                6,52 GB
Current LE             1668
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:0
 
--- Logical volume ---
LV Name                /dev/calero/swap_1
VG Name                calero
LV UUID                sGM4EI-QMBx-428v-B7nc-OcHB-KSnj-H9I1ze
LV Write Access        read/write
LV Status              available
# open                 2
LV Size                2,53 GB
Current LE             648
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:1
 
--- Logical volume ---
LV Name                /dev/calero/home
VG Name                calero
LV UUID                jlNSaR-X2mN-l6Cs-epeu-PDRv-3iqi-izAUBP
LV Write Access        read/write
LV Status              available
# open                 1
LV Size                65,24 GB
Current LE             16702
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           254:2

2. Renombramos el Volumen Lógico que queramos:

lvrename /dev/calero/home nuevo_nombre_lv

Añadimos el disco físicamente

Al hacer un fdisk veremos que lo tenemos sin particionar

# fdisk -l

Disk /dev/hda: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1          13      104391   83  Linux
/dev/hda2              14        1305    10377990   8e  Linux LVM

Disk /dev/hdd: 2147 MB, 2147483648 bytes
16 heads, 63 sectors/track, 4161 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

Disk /dev/hdd doesn't contain a valid partition table

Con fdisk creamos una partición en /dev/hdb1 y la creamos tipo LVM:

# fdisk /dev/hdd
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won't be recoverable.


The number of cylinders for this disk is set to 4161.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): n
Command action
   e   extended
   p   primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-4161, default 1): 
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-4161, default 4161): 
Using default value 4161

Command (m for help): t
Selected partition 1
Hex code (type L to list codes): 8e
Changed system type of partition 1 to 8e (Linux LVM)

Command (m for help): p

Disk /dev/hdd: 2147 MB, 2147483648 bytes
16 heads, 63 sectors/track, 4161 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdd1               1        4161     2097112+  8e  Linux LVM

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

# pvcreate /dev/hdd1 
Physical volume "/dev/hdd1" successfully created

# vgextend VolGroup00 /dev/hdd1 
Volume group "VolGroup00" successfully extended

De los 2Gb añadimos solo 1Gb:

# lvextend -L +1G /dev/VolGroup00/LogVol00 /dev/hdd1 

Extending logical volume LogVol00 to 10.12 GB
Logical volume LogVol00 successfully resized

Vemos que todavía queda 1Gb libre (Free PE/Size 32/1.00GB):

# vgdisplay 

1. – Volume group —

VG Name VolGroup00

System ID             
Format                lvm2
Metadata Areas        3
Metadata Sequence No  6
VG Access             read/write
VG Status             resizable
MAX LV                0
Cur LV                2
Open LV               2
Max PV                0
Cur PV                3
Act PV                3
VG Size               11.88 GB
PE Size               32.00 MB
Total PE              380
Alloc PE / Size       348 / 10.88 GB
Free  PE / Size       32 / 1.00 GB
VG UUID               bB6L14-jB12-AmVc-IhZ0-PsK0-2kUe-nAvaTZ

Para ampliar al máximo de file system es sin ningún parámetro:

# lvextend /dev/VolGroup00/LogVol00 /dev/hdd1 

Extending logical volume LogVol00 to 11.09 GB
Logical volume LogVol00 successfully resized

# resize2fs /dev/VolGroup00/LogVol00

resize2fs 1.39 (29-May-2006)
Filesystem at /dev/VolGroup00/LogVol00 is mounted on /; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/LogVol00 to 2654208 (4k) blocks.
The filesystem on /dev/VolGroup00/LogVol00 is now 2654208 blocks long.

http://www.linuxnetadmin.com/2008/01/how-to-add-disk-space-with-lvm-on-linux.html