itramblings

Ramblings from an IT manager and long time developer.

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Adding a new drive to linux

 

Determine Drive Information

We assume that the hard drive is physically installed and detected by the BIOS.

To determine the path that your system has assigned to the new hard drive, open a terminal and run:

sudo lshw -C disk

IconsPage/IconExample48.png This should produce output similar to this sample:

  *-disk
       description: ATA Disk
       product: IC25N040ATCS04-0
       vendor: Hitachi
       physical id: 0
       bus info: ide@0.0
       logical name: /dev/sdb
       version: CA4OA71A
       serial: CSH405DCLSHK6B
       size: 37GB
       capacity: 37GB

 

Be sure to note the “logical name” entry, as it will be used several times throughout this guide.

 

Command Line Partitioning

You’ll be using “fdisk” to accomplish this. Refer back to the logical name you noted from earlier. For illustration, I’ll use /dev/sdb, and assume that you want a single partition on the disk, occupying all the free space.

If the number of cylinders in the disk is larger than 1024 (and large hard drives always have more), it 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)

Otherwise, this will not negatively affect you. 

1) Initiate fdisk with the following command:

  •   sudo fdisk /dev/sdb 

2) Fdisk will display the following menu:

  •   Command (m for help): m <enter>
      Command action
       a   toggle a bootable flag
       b   edit bsd disklabel
       c   toggle the dos compatibility flag
       d   delete a partition
       l   list known partition types
       m   print this menu
       n   add a new partition
       o   create a new empty DOS partition table
       p   print the partition table
       q   quit without saving changes
       s   create a new empty Sun disklabel
       t   change a partition's system id
       u   change display/entry units
       v   verify the partition table
       w   write table to disk and exit
       x   extra functionality (experts only)
    
      Command (m for help):

3) We want to add a new partition. Type “n” and press enter.

  Command action
   e   extended
   p   primary partition (1-4)

4) We want a primary partition. Enter “p” and enter.

  Partition number (1-4):

5) Since this will be the only partition on the drive, number 1. Enter “1” and enter. 

  Command (m for help):

If it asks about the first cylinder, just type “1” and enter. (We are making 1 partition to use the whole disk, so it should start at the beginning.)

6) Now that the partition is entered, choose option “w” to write the partition table to the disk. Type “w” and enter.

  The partition table has been altered!

7) If all went well, you now have a properly partitioned hard drive that’s ready to be formatted. Since this is the first partition, Linux will recognize it as /dev/sdb1, while the disk that the partition is on is still /dev/sdb.

 

Command Line Formatting

To format the new partition as ext3 file system (best for use under Ubuntu):

  •   sudo mkfs -t ext3 /dev/sdb1

To format the new partition as fat32 file system (best for use under Ubuntu & Windows):

  •   sudo mkfs -t fat32 /dev/sdb1

 

As always, substitute “/dev/sdb1” with your own partition’s path.

 

Modify Reserved Space (Optional)

When formatting the drive as ext2/ext3, 5% of the drive’s total space is reserved for the super-user (root) so that the operating system can still write to the disk even if it is full. However, for disks that only contain data, this is not necessary.

NOTE: You may run this command on a fat32 file system, but it will do nothing; therefore, I highly recommend not running it.

You can adjust the percentage of reserved space with the “tune2fs” command, like this:

 sudo tune2fs -m 1 /dev/sdb1

This example reserves 1% of space – change this number if you wish.

  • (i) Using this command does not change any existing data on the drive. You can use it on a drive which already contains data.

 

Create A Mount Point

Now that the drive is partitioned and formatted, you need to choose a mount point. This will be the location from which you will access the drive in the future. I would recommend using a mount point with “/media”, as it is the default used by Ubuntu. For this example, we’ll use the path “/media/mynewdrive”

  •   sudo mkdir /media/mynewdrive

Now we are ready to mount the drive to the mount point.

 

Mount The Drive

 

You can choose to have the drive mounted automatically each time you boot the computer, or manually only when you need to use it.

 

Automatic Mount At Boot

Note: Ubuntu now recommends to use UUID instead, see the instructions here:https://help.ubuntu.com/community/UsingUUID

You’ll need to edit /etc/fstab:

  •   sudo vi -Bw /etc/fstab

Note: https://help.ubuntu.com/community/Fstab#Editing_fstab

Add this line to the end (for ext3 file system):

  •   /dev/sdb1    /media/mynewdrive   ext3    defaults     0        2

Add this line to the end (for fat32 file system):

  •   /dev/sdb1    /media/mynewdrive   vfat    defaults     0        2

    The defaults part may allow you to read, but not write. To write other partition and FAT specific options must be used. If gnome nautilus is being used, use the right-click, mount method, from computer folder. Then launch the mount command from terminal, no options. The last entry should be the FAT drive and and look something like:

      /dev/sda5 on /media/mynewdrive type vfat (rw,nosuid,nodev,uhelper=hal,shortname=mixed,uid=1000,utf8,umask=077,flush)

    All of the parts between the parenthesis are the mount options and should replace “defaults” in the fstab file. The “2” at the end instructs your system to run a quick file system check on the hard drive at every boot. Changing it to “0” will skip this. Run ‘man fstab’ for more info here.

You can now run “sudo mount -a” (or reboot the computer) to have the changes take effect.

If you want to allow a normal user to create files on this drive, you can either give this user ownership of the top directory of the drive filesystem: (replace USERNAME with the username)

  •   sudo chown -R USERNAME:USERNAME /media/mynewdrive

or in a more flexible way, practical if you have several users, allow for instance the users in the plugdev group (usually those who are meant to be able to mount removable disks, desktop users) to create files and sub-directories on the disk:

  •   sudo chgrp plugdev /media/mynewdrive
      sudo chmod g+w /media/mynewdrive
      sudo chmod +t /media/mynewdrive

The last “chmod +t” adds the sticky bit, so that people can only delete their own files and sub-directories in a directory, even if they have write permissions to it (see man chmod).

 

Manually Mount

Alternatively, you may want to manually mount the drive every time you need it.

For manual mounting, use the following command:

sudo mount /dev/sdb1 /media/mynewdrive 

When you are finished with the drive, you can unmount it using:

 

sudo umount /media/mynewdrive