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Category: Linux Admin

  • Sizing Non-LVM Root Partitions

    Recently, I was faced with a busy production server with a space problem where the root partition was near capacity.

    After some research, I determined that it was possible to add space to the RHEL root partition but felt that this would be risky as I did not have experience making this sort of change.

    Fortunately, I was able to spin up a clone of this system in our QA Environment to test the procedure that I explain below.

    Overview

    • Allocate Disk Space to Virtual Machine In VMWare vSphere
    • Backup Virtual Machine
    • Execute Steps Below
    • Test Services including Backup Process

    Steps

    1. Login(ssh) to Server and Sudo to Root (su)
      ssh server-name
      sudo su

    2. List Disk Partitions
      fdisk -l

      Disk /dev/sda: 1319.4GB, 1319413952512 bytes
      255 heads, 63 sectors/track, 160509 cylinders

      Disk identifier: 0x00000000

      Device Boot Start End Blocks Id System
      /dev/sda1 1 8355 67108864 82 Linux swap / Solaris
      /dev/sda2 * 8355 133675 1006631936 83 Linux

    3. Determine unique device Identifiers
      blkid

      /dev/sda2: 970ab9b7-e71a-45da-907c-1b4005c1c8a9 /
      /dev/sda1: 43d83161-4d58-4cb5-8d39-4511f693cc87 swap

    4. Check mount list
      cat /etc/fstab

    5. Modify /dev/sda Disk using fdisk command
      fdisk /dev/sda

    6. In fdisk – List, delete, partition 2
      p d 2

    7. List, Add New Partition 2, Start 8355, End 160509, write partition table and quit
      p n p 2 8355 160509 W

    8. Modify /dev/sda Disk partition using fdisk command
      fdisk /dev/sda

      Check Partition ID and change Partition Type to 83 (Linux) If Incorrect.
    9. List, Set, Parition 2, Type 83 (Linux), List and Write Partition Table.
      p t 2 83 p w

    10. Use blkid command to check partition identifier is the same and move on to the next step or change identifier in /etc/fstab file to the new identifier value. *** Please Note *** Failure to change the value in the /etc/fstab file will most likely result in the system not booting.
      blkid

    11. Restart VM, Login, Check Disk Size, Update File System, Partitions, and Disk Size
      init 6
      ssh server-name
      sudo su
      df –h

      Filesystem Size Used Avail Use% Mounted on
      /dev/sda2 945G 756G 142G 85% /
      tmpfs 32G 0 32G 0% /dev/shm

      resize2fs /dev/sda2
      resize2fs 1.41.12 (17-May-2010)
      Filesystem at /dev/sda2 is mounted on /; online resizing required
      old desc_blocks = 60, new_desc_blocks = 73
      Performing an online resize of /dev/sda2 to 305343851 (4k) blocks.
      The filesystem on /dev/sda2 is now 305343851 blocks long.

      fdisk -l

      Disk /dev/sda: 1319.4 GB, 1319413952512 bytes
      255 heads, 63 sectors/track, 160409 cylinders
      Units = cylinders of 16065 * 512 = 8225280 bytes
      Sector size (logical/physical): 512 bytes / 512 bytes
      I/O size (minimum/optimal): 512 bytes / 512 bytes
      Disk identifier: 0x00000000

      Device Boot Start End Blocks Id System
      /dev/sda1 1 8355 67108864 82 Linux swap / Solaris
      /dev/sda2 8355 160409 1221375404+ 83 Linux


      df –h

      Filesystem Size Used Avail Use% Mounted on
      /dev/sda2 1.2T 756G 334G 70% /
      tmpfs 32G 0 32G 0% /dev/shm

    Outcomes

    1. Root Partition Disk Space Increased from 945G to 1.2T by resizing disk.
    2. Database Backups stopped failing
    3. Data migration continued successfully