amazon-ec2centosdisk-partitioning

unable to resize root partition on EC2 centos


i created my EC2 Machine using Community Image of Centos 6.3 x64. i have added a 35 GB disk. Now when i do #df -h

Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda1            7.9G  1.2G  6.4G  16% /
tmpfs                 7.3G     0  7.3G   0% /dev/shm

my disk is 35GB but its showing 8 GB in root and 7 as tmpfs.

i tried to use resize2fs but it didnt work on centos. disk has ext4 partation..

# resize2fs /dev/xvda
resize2fs 1.41.12 (17-May-2010)
resize2fs: Device or resource busy while trying to open /dev/xvda
Couldn't find valid filesystem superblock.

or even if i tried resize2fs /dev/xvda1 it says device has nothing to do.

any idea or other way, its my root disk(/). so cant unmount it.


Solution

  • i found a way to do that, resize2fs not working in case not sure why but it says device or resource busy. i found a very good article on resizedisk using fdisk we can increase block size by deleting and creating it and Make the partition bootable. all it requires is a reboot. it wont effect your data if you use same start cylinder.

    # df -h  <<1>>
    
    Filesystem      Size  Used Avail Use% Mounted on
    /dev/xvda1      6.0G  2.0G  3.7G  35% / 
    tmpfs            15G     0   15G   0% /dev/shm
    
    # fdisk -l  <<2>>
    
    Disk /dev/xvda: 21.5 GB, 21474836480 bytes
    97 heads, 17 sectors/track, 25435 cylinders
    Units = cylinders of 1649 * 512 = 844288 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x0003b587
    
        Device Boot      Start         End      Blocks   Id  System
    /dev/xvda1   *           2        7632     6291456   83  Linux
    
    # fdisk /dev/xvda  <<3>>
    
    WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
             switch off the mode (command 'c') and change display units to
             sectors (command 'u').
    
    Command (m for help): u  <<4>>
    Changing display/entry units to sectors
    
    Command (m for help): p  <<5>>
    
    Disk /dev/xvda: 21.5 GB, 21474836480 bytes
    97 heads, 17 sectors/track, 25435 cylinders, total 41943040 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x0003b587
    
        Device Boot      Start         End      Blocks   Id  System
    /dev/xvda1   *        2048    12584959     6291456   83  Linux
    
    Command (m for help): d  <<6>>
    Selected partition 1
    
    Command (m for help): n  <<7>>
    Command action
       e   extended
       p   primary partition (1-4)
    p  <<8>>
    Partition number (1-4): 1  <<9>>
    First sector (17-41943039, default 17): 2048  <<10>>
    Last sector, +sectors or +size{K,M,G} (2048-41943039, default 41943039): <<11>>
    Using default value 41943039
    
    Command (m for help): p <<12>>
    
    Disk /dev/xvda: 21.5 GB, 21474836480 bytes
    97 heads, 17 sectors/track, 25435 cylinders, total 41943040 sectors
    Units = sectors of 1 * 512 = 512 bytes
    Sector size (logical/physical): 512 bytes / 512 bytes
    I/O size (minimum/optimal): 512 bytes / 512 bytes
    Disk identifier: 0x0003b587
    
        Device Boot      Start         End      Blocks   Id  System
    /dev/xvda1            2048    41943039    20970496   83  Linux
    
    Command (m for help): a  <<13>>
    Partition number (1-4): 1  <<14>>
    
    
    Command (m for help): w  <<15>>
    The partition table has been altered!
    
    Calling ioctl() to re-read partition table.
    
    WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
    The kernel still uses the old table. The new table will be used at
    the next reboot or after you run partprobe(8) or kpartx(8)
    Syncing disks.
    
    # reboot  <<16>>
    
    <wait>
    
    # df -h  <<17>>
    Filesystem      Size  Used Avail Use% Mounted on
    /dev/xvda1       20G  2.0G   17G  11% / 
    tmpfs            15G     0   15G   0% /dev/shm
    
    # resize2fs /dev/xvda1  <<18>>
    resize2fs 1.41.12 (17-May-2010)
    The filesystem is already 5242624 blocks long.  Nothing to do!