Difference between revisions of "Add new partitions to an existing system"

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(Make introduction more general.)
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[[Category:File systems (English)]]
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[[Category:File systems]]
{{i18n|Add new partitions to an existing system}}
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{{Article summary start}}
{{Poor writing}}
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{{Article summary text|This article discusses the process of changing partitions in an existing environment.}}
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{{Article summary heading|Related}}
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{{Article summary text|[[Beginners'_Guide#Partitioning_hard_disks:_General_information|Partitioning Hard Disks]]: Basic introduction to partitioning on Arch Linux on the Beginner's Guide.}}
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{{Article summary wiki|Gparted}}: Commonly used partitioning program.
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{{Article summary end}}
  
== Introduction ==
+
You may find yourself in the situation where you either want to create a new partition to give yourself more flexibility (for example, for backup operations), or you are forced to use new partition(s) because your original is full and to free up space you need to move data from the full partition to a new one.
  
You may find yourself in the situation where you either:
+
As an easy alternative, you can always download a copy of another operating system such as [http://www.ubuntu.com Ubuntu] and boot into a live media version ([[USB Installation Media|Arch USB Installation Media guide]]). Newer versions of Ubuntu include [[Gparted]].
* want to create a new partition to give yourself more flexibility, for example for backup operations.
+
{{Warning|Be sure to at least read through all the steps in this guide before making any real changes. There is always a risk for losing your data when adjusting partitions.}}
* are forced to use new partition(s) because your original is full and to free up space you need to move data from the full partition to a new one.  
+
  
Here are the steps to add new partition:
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== Preamble ==
 +
 
 +
Here are the steps involved with adding new partitions:
 
# Create new partitions.
 
# Create new partitions.
 
# Mount the new partitions in a temporary location.
 
# Mount the new partitions in a temporary location.
Line 18: Line 23:
  
 
== Creating the New Partitions ==
 
== Creating the New Partitions ==
{{Warning|at this stage be careful that other partitions are not mistakenly corrupted}}
+
{{Warning|Changing, Resizing and/or Creating partitions has the VERY REAL potential to cause DATA LOSS Use common sense. BACKUP ANYTHING YOU DO NOT WANT TO LOSE!}}
  
 
New partitions can be created either on previously unpartitioned sections of an existing disk (or raid array in my case) or simply on an additional newly installed drive.  
 
New partitions can be created either on previously unpartitioned sections of an existing disk (or raid array in my case) or simply on an additional newly installed drive.  
  
You will need your filesystems to be '''UNMOUNTED''' when you make changes such as adding new partitions to the free space on your disk or shrinking partitions. Therefore you will need to boot into an environment such as provided by the install CD in '''"Rescue"''' mode, the [[Gparted-Live]] CD or another live CD with the necessary utilities.  
+
You will need your filesystems to be '''UNMOUNTED''' when you make changes such as adding new partitions to the free space on your disk or shrinking partitions. Therefore you will need to boot into an environment such as provided by the install CD in '''Rescue''' mode.  
  
Command line utilities such as fdisk, cfdisk or sfdisk can be used, but if you are unfamiliar with creating partitions and filesystems I would recommend downloading and using the [[Gparted-Live]] iso; it provides a nice gui and additional checks to make sure what you are doing is okay.  
+
Command line utilities such as fdisk, cfdisk or sfdisk can be used, but if you are unfamiliar with creating partitions and filesystems [[Gparted-Live]] iso is recommended. It provides a nice gui and additional checks to make sure what you are doing is okay. See also [[GParted]] for how to use GParted.
 
+
You can download GParted here: http://gparted.sourceforge.net/download.php
+
'''See the note about its use on some HP Pavilion Computers'''
+
 
+
{{Warning|Changing, Resizing and/or Creating partitions has the VERY REAL potential to cause DATA LOSS Use common sense. BACKUP ANYTHING YOU DO NOT WANT TO LOSE!}}
+
 
+
With that cautionary statement, you can take comfort knowing that changing, resizing, creating and removing partitions is what the partitioning tools were created for. They work. Just make sure you understand what your are doing with the software and do not do anything strange (like clicking buttons willy-nilly or randomly trying out all of the commands available in the packages) and you should be just fine.
+
  
 
=== Extended Growth & Logical Partitioning ===
 
=== Extended Growth & Logical Partitioning ===
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You will need to create a filesystem on the new partitions with 'mkfs -t <fstype>' or you may select the desired filesystem when defining your partition with Gparted. If you do not know which filesystem you are using, then from the command line type "df -hT" and check the type column.
 
You will need to create a filesystem on the new partitions with 'mkfs -t <fstype>' or you may select the desired filesystem when defining your partition with Gparted. If you do not know which filesystem you are using, then from the command line type "df -hT" and check the type column.
  
== Moving Existing Data to the New Partitions ==
+
== Moving Existing Data to the New Partition ==
  
To benefit from the extra space provided by the new partitions, the new partitions need to be integrated into the filesystem. In my case I was replacing the directories {{ic|/srv}} and {{ic|/var}} with the new partitions {{ic|/srv}} and {{ic|/var}}. The solution:
+
To benefit from the extra space provided by the new partitions, the new partitions need to be integrated into the filesystem.  
#copy everything from the existing directories to the new partitions
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#delete the contents of the existing {{ic|/srv}} and {{ic|/var}} directories
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#mount the new partitions under {{ic|/srv}} and {{ic|/var}}
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{{Warning|check to confirm a good copy}}
+
  
 +
Files should not be written to the parts of the filesystem you are moving during this process. The safest way to accomplish the copy and delete is to either boot from your install cd into rescue mode and create mount points to hold your {{ic|/}} filesystem and the new partitions, or alternatively shutdown anything that could write to or read from the existing directories. Fro example, for {{ic|/var}}, syslog-ng needed to be shutdown. If using dmraid, issue "dmraid -ay" to activate your raid sets when booting from the install CD into rescue mode.
  
Files should not be written to the parts of the filesystem you are moving during this process. The safest way to accomplish the copy and delete is to either boot from your install cd into rescue mode and create mount points to hold your {{ic|/}} filesystem and the new partitions, or alternatively shutdown anything that could write to or read from the existing directories. {{ic|/srv}} was not an issue, but for {{ic|/var}}, syslog-ng needed to be shutdown. (If using dmraid, issue "dmraid -ay" to activate your raid sets when booting from the install CD into rescue mode.)
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The basic process (as root) is:
  
My new partitions were {{ic|/dev/mapper/nvidia_ecaejfdip9}} and {{ic|/dev/mapper/nvidia_ecaejfdip10}}. Usually they are similar to {{ic|/dev/sda5}} so substitute as necessary. The basic process (as root) is:
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Stop any processes that might write to the old directories.
 +
# /etc/rc.d/syslog-ng stop
  
Stop any processes that might write to the old directories.
 
{{bc| # /etc/rc.d/syslog-ng stop}}
 
 
 
Create temporary mount points for your new partitions.
 
Create temporary mount points for your new partitions.
{{bc| # mkdir /mnt/newsrv
+
  # mkdir /mnt/newtemp
  # mkdir /mnt/newvar}}
+
 
+
 
Mount the new partitions on the temporary mount points.
 
Mount the new partitions on the temporary mount points.
{{bc| # mount /dev/mapper/nvidia_ecaejfdip9 /mnt/newsrv
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  # mount /dev/sda5 /mnt/newtemp
  # mount /dev/mapper/nvidia_ecaejfdip10 /mnt/newvar}}
+
  
{{Warning|before doing this ensure that the system does not still need read or write access to these folders}}
+
{{Warning|Before doing this ensure that the system does not still need read or write access to these folders}}
 
Copy the information from the old directories to the new partitions.
 
Copy the information from the old directories to the new partitions.
{{bc| # cp -a /srv/* /mnt/newsrv
+
  # cp -a /olddir /mnt/newtemp
  # cp -a /var/* /mnt/newvar}}
+
 
+
 
Confirm the information was written to the new partitions with ls, diff, etc. When you are certain the information was written correctly to the new partitions delete the information from the old directories.
 
Confirm the information was written to the new partitions with ls, diff, etc. When you are certain the information was written correctly to the new partitions delete the information from the old directories.
 
+
  # rm -r /olddir
 
+
  {{bc| # rm -r /srv/*
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# rm -r /var/*}}
+
  
 
== Remounting the New Partitions on the Filesystem ==
 
== Remounting the New Partitions on the Filesystem ==
  
Now you have new partitions containing your data and have deleted the original copy of the data from the {{ic|/}} filesystem to free-up space. Next the new partition(s) should be unmounted from their temporary location(s) and assigned their proper place in the filesystem.
+
Next the new partition(s) should be unmounted from their temporary location(s) and assigned their proper place in the filesystem.
  
=== Provisional remounting and checking ===
+
=== Manually remounting and checking ===
  
# Unmount the new partitions from the temporary mount point
+
Unmount the new partitions from the temporary mount point
  umount /mnt/newsrv
+
  umount /mnt/newtemp
umount /mnt/newvar
+
+
# Mount the new partitions as /srv and /var
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mount /dev/mapper/nvidia_ecaejfdip9 /srv
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mount /dev/mapper/nvidia_ecaejfdip10 /var
+
  
Now the new partitions are in the proper location in the filesystem and you can confirm the new room you have created on {{ic|/}} with "df -h"
+
Mount the new partitions as /newdir
 +
mount /dev/sda5 /newdir
  
[16:19 archangel:/home/david] # df -h
+
Now the new partitions are in the proper location in the filesystem and you can confirm the new room with {{ic|df -h}}
Filesystem            Size  Used Avail Use% Mounted on
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/dev/mapper/nvidia_ecaejfdip5
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                      19G  11G  7.3G  59% /
+
none                  2.0G    0  2.0G  0% /dev/shm
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/dev/mapper/nvidia_ecaejfdip6
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                      114M  17M  92M  15% /boot
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/dev/mapper/nvidia_ecaejfdip7
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                      37G  12G  24G  32% /home
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/dev/mapper/nvidia_ecaejfdip9
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                      15G  165M  14G  2% /mnt/var
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/dev/mapper/nvidia_ecaejfdip10
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                      29G  7.4G  20G  27% /srv
+
  
 
=== Permanent remounting ===
 
=== Permanent remounting ===
  
 
Finally make the new changes permanent by adding the new mount configuration to {{ic|/etc/fstab}}. As root edit {{ic|/etc/fstab}} adding something similar to the following corresponding to your own new partitions:
 
Finally make the new changes permanent by adding the new mount configuration to {{ic|/etc/fstab}}. As root edit {{ic|/etc/fstab}} adding something similar to the following corresponding to your own new partitions:
 
# New Partitions, {{ic|/srv}} and {{ic|/var}} on separate partitions
 
 
   
 
   
  /dev/mapper/nvidia_ecaejfdip9 /var ext3 defaults 0 1
+
  /dev/sda5 /newdir ext3 defaults 0 2
/dev/mapper/nvidia_ecaejfdip10 /srv ext3 defaults 0 1
+
  
 
(See the [[fstab]] article for more details.)
 
(See the [[fstab]] article for more details.)
  
 
If you have disabled any running processes, restart or enable them, check the files on your new partitions to insure all is well and check the logs for any permission errors. Then reboot and make sure it all works as expected.
 
If you have disabled any running processes, restart or enable them, check the files on your new partitions to insure all is well and check the logs for any permission errors. Then reboot and make sure it all works as expected.

Revision as of 20:03, 16 January 2013

Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary text Template:Article summary wiki: Commonly used partitioning program. Template:Article summary end

You may find yourself in the situation where you either want to create a new partition to give yourself more flexibility (for example, for backup operations), or you are forced to use new partition(s) because your original is full and to free up space you need to move data from the full partition to a new one.

As an easy alternative, you can always download a copy of another operating system such as Ubuntu and boot into a live media version (Arch USB Installation Media guide). Newer versions of Ubuntu include Gparted.

Warning: Be sure to at least read through all the steps in this guide before making any real changes. There is always a risk for losing your data when adjusting partitions.

Preamble

Here are the steps involved with adding new partitions:

  1. Create new partitions.
  2. Mount the new partitions in a temporary location.
  3. Copy the existing files from old partition to the newly created partitions in their temporary locations.
  4. Delete the files under the original directories
  5. Move new partition from their temporary mount points to their permanent homes
  6. Update fstab accordingly.

Creating the New Partitions

Warning: Changing, Resizing and/or Creating partitions has the VERY REAL potential to cause DATA LOSS Use common sense. BACKUP ANYTHING YOU DO NOT WANT TO LOSE!

New partitions can be created either on previously unpartitioned sections of an existing disk (or raid array in my case) or simply on an additional newly installed drive.

You will need your filesystems to be UNMOUNTED when you make changes such as adding new partitions to the free space on your disk or shrinking partitions. Therefore you will need to boot into an environment such as provided by the install CD in Rescue mode.

Command line utilities such as fdisk, cfdisk or sfdisk can be used, but if you are unfamiliar with creating partitions and filesystems Gparted-Live iso is recommended. It provides a nice gui and additional checks to make sure what you are doing is okay. See also GParted for how to use GParted.

Extended Growth & Logical Partitioning

Partitions come in three main flavors: Primary, Extended and Logical. An Extended partition is for the most part just a "wrapper" to contain logical partitions.

If you have a typical Linux partition scheme, then you probably have a single "extended" partition with "logical" partitions of '/', '/home' and possibly a '/boot' partition. Your logical partitions will probably completely fill the extended partition they reside in. Before you can add additional partitions, you must grow the current extended partition to make room for your new logical partitions, or you can create a new extended partition. I prefer to grow the extended partition then add the new logical partitions. I find no need for primary partitions unless dual booting windows.

You will need to create a filesystem on the new partitions with 'mkfs -t <fstype>' or you may select the desired filesystem when defining your partition with Gparted. If you do not know which filesystem you are using, then from the command line type "df -hT" and check the type column.

Moving Existing Data to the New Partition

To benefit from the extra space provided by the new partitions, the new partitions need to be integrated into the filesystem.

Files should not be written to the parts of the filesystem you are moving during this process. The safest way to accomplish the copy and delete is to either boot from your install cd into rescue mode and create mount points to hold your / filesystem and the new partitions, or alternatively shutdown anything that could write to or read from the existing directories. Fro example, for /var, syslog-ng needed to be shutdown. If using dmraid, issue "dmraid -ay" to activate your raid sets when booting from the install CD into rescue mode.

The basic process (as root) is:

Stop any processes that might write to the old directories.

# /etc/rc.d/syslog-ng stop

Create temporary mount points for your new partitions.

# mkdir /mnt/newtemp

Mount the new partitions on the temporary mount points.

# mount /dev/sda5 /mnt/newtemp
Warning: Before doing this ensure that the system does not still need read or write access to these folders

Copy the information from the old directories to the new partitions.

# cp -a /olddir /mnt/newtemp

Confirm the information was written to the new partitions with ls, diff, etc. When you are certain the information was written correctly to the new partitions delete the information from the old directories.

# rm -r /olddir

Remounting the New Partitions on the Filesystem

Next the new partition(s) should be unmounted from their temporary location(s) and assigned their proper place in the filesystem.

Manually remounting and checking

Unmount the new partitions from the temporary mount point

umount /mnt/newtemp

Mount the new partitions as /newdir

mount /dev/sda5 /newdir

Now the new partitions are in the proper location in the filesystem and you can confirm the new room with df -h

Permanent remounting

Finally make the new changes permanent by adding the new mount configuration to /etc/fstab. As root edit /etc/fstab adding something similar to the following corresponding to your own new partitions:

/dev/sda5 /newdir ext3 defaults 0 2

(See the fstab article for more details.)

If you have disabled any running processes, restart or enable them, check the files on your new partitions to insure all is well and check the logs for any permission errors. Then reboot and make sure it all works as expected.