linux-raw-filesystem-management

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13y, 61d ago [edited]

Linux Raw File system Management

Pretend we have added a new disk to our computer.

The operating system has detected this new disk as device /dev/xvdf.

The following documents the steps we need to take to use this new space.

Partition the device

You may cut the device into separate logical disks.

In my case I want to use the whole disk

sudo fdisk /dev/xvdf 
# choose needed settings

Format the partition with a filesystem

We want to use ext4 so we do

sudo mkfs.ext4 /dev/xvdf

 mke2fs 1.42 (29-Nov-2011)
 Filesystem label=
 OS type: Linux
 Block size=4096 (log=2)
 Fragment size=4096 (log=2)
 Stride=0 blocks, Stripe width=0 blocks
 6553600 inodes, 26214400 blocks
 1310720 blocks (5.00%) reserved for the super user
 First data block=0
 Maximum filesystem blocks=4294967296
 800 block groups
 32768 blocks per group, 32768 fragments per group
 8192 inodes per group
 Superblock backups stored on blocks: 
        32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
        4096000, 7962624, 11239424, 20480000, 23887872  

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

Mount and test the new filesystem

sudo mount /dev/xvdf1 /mnt
touch /mnt/testfile
ls /mnt
sudo umount /mnt
ls /mnt
sudo mount /dev/xvdf1 /mnt

Automatically mount partition at system boot

Add an entry into /etc/fstab for new partition.

/dev/xvdf1   /mnt        ext4   defaults        0 0

Remount read-only or read-write

Sometimes live disks and rescue modes mount your partitions for you. In my case the rescue was mounting root partition as read-only, and I needed to remove an entry in /etc/fstab. This command will remount a partition with rw:

mount -o remount,rw /dev/mapper/VolGroup00-LogVol0 /

This allowed me to edit /etc/fstab, remove the bad entry and reboot. The server came back online. We still need to figure out what happened to the disk, try to recover it.

Linux Raw File system Management
###########################################

Pretend we have added a new disk to our computer.

The operating system has detected this new disk as device /dev/xvdf.

The following documents the steps we need to take to use this new space.

Partition the device
========================

You may cut the device into separate logical disks.

In my case I want to use the whole disk

.. code-block:: bash

sudo fdisk /dev/xvdf 
 # choose needed settings

Format the partition with a filesystem
========================================

We want to use ext4 so we do

.. code-block:: bash

sudo mkfs.ext4 /dev/xvdf

mke2fs 1.42 (29-Nov-2011)
  Filesystem label=
  OS type: Linux
  Block size=4096 (log=2)
  Fragment size=4096 (log=2)
  Stride=0 blocks, Stripe width=0 blocks
  6553600 inodes, 26214400 blocks
  1310720 blocks (5.00%) reserved for the super user
  First data block=0
  Maximum filesystem blocks=4294967296
  800 block groups
  32768 blocks per group, 32768 fragments per group
  8192 inodes per group
  Superblock backups stored on blocks: 
         32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208, 
         4096000, 7962624, 11239424, 20480000, 23887872

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

Mount and test the new filesystem
=======================================

.. code-block:: bash

sudo mount /dev/xvdf1 /mnt
 touch /mnt/testfile
 ls /mnt
 sudo umount /mnt
 ls /mnt
 sudo mount /dev/xvdf1 /mnt

Automatically mount partition at system boot
=================================================

Add an entry into /etc/fstab for new partition.

.. code-block:: text

/dev/xvdf1   /mnt        ext4   defaults        0 0

Remount read-only or read-write
===================================

Sometimes live disks and rescue modes mount your partitions for you.  In my case the rescue was mounting root partition as read-only, and I needed to remove an entry in /etc/fstab.  This command will remount a partition with rw:

.. code-block:: bash

mount -o remount,rw /dev/mapper/VolGroup00-LogVol0 /
 
This allowed me to edit /etc/fstab, remove the bad entry and reboot.  The server came back online.  We still need to figure out what happened to the disk, try to recover it.

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