Hack The Sec-Leading Resource Of Linux Tutorial: Volume-Resize

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Resize root EBS Volume on AWS Linux Instance</h2>
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I have created a new <a href="http://www.hackthesec.co.in/search/label/Centos" target="_blank">CentOS </a>Linux instance. I had selected 50GB of root volume during creating of instance but when system comes online it was showing only 8GB of disk is usable. I tried to resize root disk using resize2fs, I get the following message</div>
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<pre class="pretty" style="background: none 0px 0px repeat scroll rgb(240, 240, 240); border-left-color: rgb(116, 183, 63); border-left-width: 3px; border-radius: 5px; border-style: none none none solid; line-height: 1.5em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 8px 20px 8px 18px; vertical-align: baseline;">root@e2c [~]# <orange>resize2fs /dev/xvda1</orange><orange style="color: orange;"> </orange>

The filesystem is already 16556731 blocks long. Nothing to do!
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So, I have following below steps and able to successfully resize volume to its ful size selected during instance creation</div>
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Step 1. Take Backups</h2>
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We strongly recommended to take full backup (AMI) of your instance before doing any changes. Also create a snapshot of root disk.</div>
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Step 2. Check Current Partitioning</h2>
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Now check the disk partitioning using following command. You can see that /dev/xvda is 53GB in size but</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">root@e2c[~]#<orange style="color: orange;"> </orange><orange>df -h </orange>

Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 8G 3.7G 4.2G 45% /
tmpfs 1.8G 0 1.8G 0% /dev/shm
/usr/tmpDSK 485M 111M 349M 25% /tmp
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<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">root@e2c [~]#<orange style="line-height: 1.3em;"> fdisk -l</orange>
Disk /dev/xvda: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 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: 0x00098461

Device Boot Start End Blocks Id System
/dev/xvda1 * 1 1045 8387584 83 Linux
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Step 3. Increase Size of Volume</h2>
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Now start with the disk re partitioning using set of following commands. Execute all the commands carefully.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">root@e2c[~]# <orange style="line-height: 1.3em;">fdisk /dev/xvda </orange>
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').
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Now change the display units to sectors using u switch.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help):<orange> u </orange>
Changing display/entry units to sectors
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Now print the partition table to check for disk details</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help):<orange> p </orange>

Disk /dev/xvda: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders, total 104857600 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: 0x00098461

Device Boot Start End Blocks Id System
/dev/xvda1 * 2048 16777215 8387584 83 Linux
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Now delete the first partition using following command.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help):<orange> d</orange>
Selected partition 1
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Now create a new partition using following commands. For the first sector enter 2048 (as shows in above command output) and for last second just press enter to select all partition.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help): <orange>n</orange>
Command action
 e extended
 p primary partition (1-4)
<orange>p</orange>
Partition number (1-4): <orange>1</orange>
First sector (63-104857599, default 63): <orange>2048</orange><orange style="color: orange;"> </orange>
Last sector, +sectors or +size{K,M,G} (2048-104857599, default 104857599): <orange>[PRESS ENTER]</orange>
Using default value 104857599
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Print the partition table again. You will see that new partition has occupied all disk space.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help): <orange>p </orange>

Disk /dev/xvda: 53.7 GB, 53687091200 bytes
255 heads, 63 sectors/track, 6527 cylinders, total 104857600 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: 0x00098461

Device Boot Start End Blocks Id System
/dev/xvda1 2048 104857599 52427776 83 Linux
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Now set the bootable flag on partition 1.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help):<orange> a </orange>
Partition number (1-4): <orange>1</orange>
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Write disk partition permanently and exit.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">Command (m for help):<orange> w </orange>
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.
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Lets reboot your system after making all above changes.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">root@e2c [~]# <orange style="line-height: 1.3em;">reboot</orange></pre>
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Lets resize file system using resize2fs command. Remember that you are resizing filesystem not formatting.</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">root@e2c [~]#<orange style="line-height: 1.3em;"> resize2fs /dev/xvda1 </orange>
resize2fs 1.41.12 (17-May-2010)
Filesystem at /dev/xvda1 is mounted on /; on-line resizing required
old desc_blocks = 1, new_desc_blocks = 4
Performing an on-line resize of /dev/xvda1 to 13106944 (4k) blocks.
The filesystem on /dev/xvda1 is now 13106944 blocks long.
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Step 4. Verify Upgraded Disk</h2>
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At this point your root volume has been resized successfully. Just verify your disk has been resizes properly</div>
<pre style="background: none 0px 0px repeat scroll rgb(60, 60, 60); border-radius: 4px; border: 1px solid rgb(229, 229, 229); line-height: 1.3em; margin-bottom: 20px; outline: 0px; overflow: auto; padding: 20px; vertical-align: baseline;">root@e2c[~]#<orange style="line-height: 1.3em;"> df -h </orange>
Filesystem Size Used Avail Use% Mounted on
/dev/xvda1 50G 6.7G 40G 15% /
tmpfs 1.8G 0 1.8G 0% /dev/shm
/usr/tmpDSK 485M 111M 349M 25% /tmp</pre>
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How to Resize root EBS Volume on AWS Linux Instance

Resize root EBS Volume on AWS Linux Instance I have created a new CentOS Linux instance . I had selected 50GB of root volume during cre...