LINUX: Aumentar la SWAP

Gracias al manejo de LVM es posible aumentar el espacio asignado a la swap en caso de requerirlo.
Seguir los pasos descritos acontinuación:

Crear volumen logico de swap de 200 megas de espacio.

[root@localhost ~]# lvcreate -L 200M -n swap2 VolGroup00
Rounding up size to full physical extent 224.00 MB
Logical volume "swap2" created
[root@localhost ~]#

Formatear el nuevo volumen de swap

[root@localhost ~]# mkswap /dev/VolGroup00/swap2
Setting up swapspace version 1, size = 234876 kB
[root@localhost ~]#

Activar la swap recién formateada

[root@localhost ~]# swapon /dev/VolGroup00/swap2

Comprobar

[root@localhost ~]# free -m
total used free shared buffers cached
Mem: 1010 526 484 0 29 367
-/+ buffers/cache: 130 880
Swap: 735 0 735
[root@localhost ~]#
[root@localhost ~]# cat /proc/swaps
Filename Type Size Used Priority
/dev/mapper/VolGroup00-LogVol00 partition 524280 0 -1
/dev/mapper/VolGroup00-swap2 partition 229368 0 -2
[root@localhost ~]#

LINUX: agregar una unidad de disco duro.

Después de agregar físicamente un nuevo hdd al server, es necesario seguir los pasos a continuación para poder utilizar la nueva unidad de almacenamiento.

Se comprueba que el SO lea el Disco duro.

[root@localhost ~]# fdisk -l

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM

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

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

Formatear el Disco Duro

[root@localhost ~]# fdisk /dev/sdb
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 1305.
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)

En el siguiente menu se debe pinchar por las opciones que se presentan en el ejemplo a continuación:

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4):
Value out of range.
Partition number (1-4): 1
First cylinder (1-1305, default 1):
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-1305, default 1305):
Using default value 1305

Command (m for help): p

Disk /dev/sdb: 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/sdb1 1 1305 10482381 83 Linux

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

Calling ioctl() to re-read partition table.
Syncing disks.
[root@localhost ~]#

Nuevamente Comprobar con el comando fdisk

[root@localhost ~]# fdisk -l

Disk /dev/sda: 21.4 GB, 21474836480 bytes
255 heads, 63 sectors/track, 2610 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 * 1 13 104391 83 Linux
/dev/sda2 14 2610 20860402+ 8e Linux LVM

Disk /dev/sdb: 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/sdb1 1 1305 10482381 83 Linux
[root@localhost ~]#

Una vez que el nuevo hw es reconocido se procede a crear el volumen fisico o PV

[root@localhost ~]# pvcreate /dev/sdb1
Physical volume "/dev/sdb1" successfully created
[root@localhost ~]#

Comprobar los volumenes fisicos y logicos

[root@localhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 19.88G 11.50G
/dev/sdb1 lvm2 -- 10.00G 10.00G
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VolGroup00 1 3 0 wz--n- 19.88G 11.50G
[root@localhost ~]#

Añadir nuestro nuevo volumen fisico al actual volumen logico que ya tenemos.

[root@localhost ~]# vgextend VolGroup00 /dev/sdb1
Volume group "VolGroup00" successfully extended
[root@localhost ~]#

Comprobar mirando como quedan los volumenes fisicos y logicos

[root@localhost ~]# pvs
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 19.88G 11.50G
/dev/sdb1 VolGroup00 lvm2 a- 9.97G 9.97G
[root@localhost ~]# vgs
VG #PV #LV #SN Attr VSize VFree
VolGroup00 2 3 0 wz--n- 29.84G 21.47G
[root@localhost ~]#

LINUX: rsync: respaldo y clonación de directorios y servidor.

Sincronizacion con ssh (para enviar data)

rsync -avz /etc 192.168.100.18:/test

Para recibir data se cambia los directorios:

rsync -avz 192.168.100.18:/test /etc

Sincronizacion de un servidor completo:

En el nuevo servidor, clonar el sistema de particiones.
En el nuevo servidor, usar rsync asi:
rsync -avz --exclude /proc --exclude/sys / 192.168.100.18:/

LINUX: Agrandar un Filesystem con LVM.

El escenario es el siguiente:
Se tiene un server Linux, no importando la distro, donde existe un LVM y sobre ello, las particiones de sistema:

Con los siguientes comandos se puede visualizar la configuración del server:


pvs: indica los volumnes fisicos. En este se tiene un solo HDD con 20GB de capacidad.

[root@localhost ~]# pvs
/dev/hdc: open failed: No medium found
PV VG Fmt Attr PSize PFree
/dev/sda2 VolGroup00 lvm2 a- 19.88G 14.50G
[root@localhost ~]#

vgs: indica los volumenes lógicos. Se ha creado un solo gran volumen lógico sobre el HDD.

[root@localhost ~]# vgs
/dev/hdc: open failed: No medium found
VG #PV #LV #SN Attr VSize VFree
VolGroup00 1 2 0 wz--n- 19.88G 14.50G
[root@localhost ~]#

lvs: particiones logicas creadas sobre el volumen lógico.

[root@localhost ~]# lvs
/dev/hdc: open failed: No medium found
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
LogVol00 VolGroup00 -wi-ao 512.00M
raiz VolGroup00 -wi-ao 4.88G
[root@localhost ~]#

Para agregar más espacio a un FS se deben seguir los siguientes pasos:
1. Crear un volumen logico
2. Formatear la particion
3. montaje del dispositivo
4. Agregar el filesystem en el fstab para que se monte cuando se inicie el server.
5. Redimensionamiento del FS: aumentar el FS.
6. Agrandar el FS hasta el maximo que da el LV

Crear un volumen logico

[root@localhost ~]# lvcreate -L 1G -n Home VolGroup00
/dev/hdc: open failed: No medium found
Logical volume "Home" created
[root@localhost ~]#

Revisar los volumenes logicos

[root@localhost ~]# lvs
/dev/hdc: open failed: No medium found
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
Home VolGroup00 -wi-a- 1.00G
LogVol00 VolGroup00 -wi-ao 512.00M
raiz VolGroup00 -wi-ao 4.88G
[root@localhost ~]#

Formatear la particion

[root@localhost ~]# mkfs -t ext3 /dev/VolGroup00/Home
mke2fs 1.39 (29-May-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
262144 inodes, 524288 blocks
26214 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=536870912
16 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912

Writing inode tables: done
Creating journal (16384 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 30 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.

montaje del dispositivo

[root@localhost ~]# mount /dev/VolGroup00/Home /home
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-raiz
4.8G 2.1G 2.4G 47% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 506M 0 506M 0% /dev/shm
/dev/mapper/VolGroup00-Home
1008M 1.3M 956M 1% /home
[root@localhost ~]#

Agregar el fs en el fstab

vi /etc/fstab
/dev/mapper/VolGroup00-Home /home ext3 defaults 1 2

comprobar si esta ok
[root@localhost ~]# mount -a
[root@localhost ~]#

Redimensionamiento del FS: aumentar el FS.

Primero hay que aumentar el LVM (la caja donde esta el FS)
[root@localhost ~]# lvresize -L +1G /dev/VolGroup00/Home
/dev/hdc: open failed: No medium found
Extending logical volume Home to 2.00 GB
Logical volume Home successfully resized
[root@localhost ~]#

comprobar

[root@localhost ~]# mount -a
[root@localhost ~]#
[root@localhost ~]#
[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-raiz
4.8G 2.1G 2.4G 47% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 506M 0 506M 0% /dev/shm
/dev/mapper/VolGroup00-Home
2.0G 68M 1.9G 4% /home

[root@localhost ~]# lvresize -L +1G /dev/VolGroup00/Home
/dev/hdc: open failed: No medium found
Extending logical volume Home to 3.00 GB
Logical volume Home successfully resized
[root@localhost ~]# lvs
/dev/hdc: open failed: No medium found
LV VG Attr LSize Origin Snap% Move Log Copy% Convert
Home VolGroup00 -wi-ao 3.00G
LogVol00 VolGroup00 -wi-ao 512.00M
raiz VolGroup00 -wi-ao 4.88G

Agrandar el FS hasta el maximo que da el LV

[root@localhost ~]# resize2fs /dev/VolGroup00/Home
resize2fs 1.39 (29-May-2006)
Filesystem at /dev/VolGroup00/Home is mounted on /home; on-line resizing required
Performing an on-line resize of /dev/VolGroup00/Home to 786432 (4k) blocks.
The filesystem on /dev/VolGroup00/Home is now 786432 blocks long.

Comprobar que ahora el FS esta al maximo del LV

[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-raiz
4.8G 2.1G 2.4G 47% /
/dev/sda1 99M 12M 82M 13% /boot
tmpfs 506M 0 506M 0% /dev/shm
/dev/mapper/VolGroup00-Home
3.0G 68M 2.8G 3% /home
[root@localhost ~]#