A Beginner's Guide To LVM - Page 3

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Submitted by falko (Contact Author) (Forums) on Sun, 2007-01-14 19:04. ::

Until now we have three logical volumes, but we don't have any filesystems in them, and without a filesystem we can't save anything in them. Therefore we create an ext3 filesystem in share, an xfs filesystem in backup, and a reiserfs filesystem in media:

mkfs.ext3 /dev/fileserver/share

server1:~# mkfs.ext3 /dev/fileserver/share
mke2fs 1.40-WIP (14-Nov-2006)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
5242880 inodes, 10485760 blocks
524288 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=0
320 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
        4096000, 7962624

Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 23 mounts or
180 days, whichever comes first.  Use tune2fs -c or -i to override.

mkfs.xfs /dev/fileserver/backup

server1:~# mkfs.xfs /dev/fileserver/backup
meta-data=/dev/fileserver/backup isize=256    agcount=8, agsize=163840 blks
         =                       sectsz=512   attr=0
data     =                       bsize=4096   blocks=1310720, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096
log      =internal log           bsize=4096   blocks=2560, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0

mkfs.reiserfs /dev/fileserver/media

server1:~# mkfs.reiserfs /dev/fileserver/media
mkfs.reiserfs 3.6.19 (2003 www.namesys.com)

A pair of credits:
Alexander  Lyamin  keeps our hardware  running,  and was very  generous  to our
project in many little ways.

Chris Mason wrote the journaling code for V3,  which was enormously more useful
to users than just waiting until  we could create a wandering log filesystem as
Hans would have unwisely done without him.
Jeff Mahoney optimized the bitmap  scanning code for V3,  and performed the big
endian cleanups.


Guessing about desired format.. Kernel 2.6.17-2-486 is running.
Format 3.6 with standard journal
Count of blocks on the device: 262144
Number of blocks consumed by mkreiserfs formatting process: 8219
Blocksize: 4096
Hash function used to sort names: "r5"
Journal Size 8193 blocks (first block 18)
Journal Max transaction length 1024
inode generation number: 0
UUID: 2bebf750-6e05-47b2-99b6-916fa7ea5398
ATTENTION: YOU SHOULD REBOOT AFTER FDISK!
        ALL DATA WILL BE LOST ON '/dev/fileserver/media'!
Continue (y/n):y
Initializing journal - 0%....20%....40%....60%....80%....100%
Syncing..ok

Tell your friends to use a kernel based on 2.4.18 or later, and especially not a
kernel based on 2.4.9, when you use reiserFS. Have fun.

ReiserFS is successfully created on /dev/fileserver/media.

Now we are ready to mount our logical volumes. I want to mount share in /var/share, backup in /var/backup, and media in /var/media, therefore we must create these directories first:

mkdir /var/media /var/backup /var/share

Now we can mount our logical volumes:

mount /dev/fileserver/share /var/share
mount /dev/fileserver/backup /var/backup
mount /dev/fileserver/media /var/media

Now run

df -h

You should see your logical volumes in the output:

server1:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2              19G  665M   17G   4% /
tmpfs                  78M     0   78M   0% /lib/init/rw
udev                   10M   88K   10M   1% /dev
tmpfs                  78M     0   78M   0% /dev/shm
/dev/sda1             137M   17M  114M  13% /boot
/dev/mapper/fileserver-share
                       40G  177M   38G   1% /var/share
/dev/mapper/fileserver-backup
                      5.0G  144K  5.0G   1% /var/backup
/dev/mapper/fileserver-media
                      1.0G   33M  992M   4% /var/media

Congratulations, you've just set up your first LVM system! You can now write to and read from /var/share, /var/backup, and /var/media as usual.

We have mounted our logical volumes manually, but of course we'd like to have them mounted automatically when the system boots. Therefore we modify /etc/fstab:

mv /etc/fstab /etc/fstab_orig
cat /dev/null > /etc/fstab

vi /etc/fstab

Put the following into it:

# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
/dev/sda2       /               ext3    defaults,errors=remount-ro 0       1
/dev/sda1       /boot           ext3    defaults        0       2
/dev/hdc        /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/fd0        /media/floppy0  auto    rw,user,noauto  0       0
/dev/fileserver/share   /var/share     ext3       rw,noatime    0 0
/dev/fileserver/backup    /var/backup      xfs        rw,noatime    0 0
/dev/fileserver/media    /var/media      reiserfs   rw,noatime    0 0

If you compare it to our backup of the original file, /etc/fstab_orig, you will notice that we added the lines:

/dev/fileserver/share   /var/share     ext3       rw,noatime    0 0
/dev/fileserver/backup    /var/backup      xfs        rw,noatime    0 0
/dev/fileserver/media    /var/media      reiserfs   rw,noatime    0 0

Now we reboot the system:

shutdown -r now

After the system has come up again, run

df -h

again. It should still show our logical volumes in the output:

server1:~# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda2              19G  665M   17G   4% /
tmpfs                  78M     0   78M   0% /lib/init/rw
udev                   10M   88K   10M   1% /dev
tmpfs                  78M     0   78M   0% /dev/shm
/dev/sda1             137M   17M  114M  13% /boot
/dev/mapper/fileserver-share
                       40G  177M   38G   1% /var/share
/dev/mapper/fileserver-backup
                      5.0G  144K  5.0G   1% /var/backup
/dev/mapper/fileserver-media
                      1.0G   33M  992M   4% /var/media


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Submitted by SN (not registered) on Thu, 2011-04-14 08:54.

There's a Zimbra backup script based on LVM, I have no idea of LVM so I searched and found this amazing topic. Thanks so much for your work.

Regards,

SN

Submitted by Navin Pathak (not registered) on Thu, 2011-03-17 13:55.

Dear Freinds,

I have started learn linux from few days and now days I am learning LVM I have search a lot of document and finaly choose your site and start working today through your guide line for LVM I have completed today near entry to fstab of logical valume so I feel very well with your documents.

Thanks a lot you all who spend a time to cretae such a nice lvm real practical.

my one suggetion is that please explain the term of PE,LE and metadata.

again thanks.

 

Regards

Navin Pathak

TTSL India.

Submitted by Anonymous (not registered) on Mon, 2010-05-03 15:31.

Great guide!

Thanks a lot - helped me out :-)