dd question, what am I doing wrong? [SOLVED]

[Daniel B. Thurman]

On 12/04/2009 01:56 PM, Tom H wrote:
>> I am copying a disk/partition to another disk/partition
>> using dd, with the following:
>>
>> BEFORE:
>> Disk1: partition#1: psize=100G, size=97.65G, used=91.23G, unused=6.42G
>> Disk2: partition#1: psize=250G, size=244.14G (newly formatted)
>>
>> I did a dd if=/dev/sda1 of=/dev/sdb1
>>
>> AFTER:
>> Disk1: partition#1: psize=100G, size=97.65G, used=91.23G, unused=6.42G
>> Disk2: partition#1: psize=250G, size=244.14G, used=237.72G, unused=6.42G
>>
>> WTF...
>>
>> Then I:
>> 1) mount /dev/sdb1 /mnt
>> 2) cd /mnt/b
>> 3) df -h .
>> Filesystem            Size  Used Avail Use% Mounted on
>> /dev/sdb1              97G   90G  1.6G  99% /mnt/b
>> 4) umount /mnt
>>
>> 5) mount /dev/sdb1 /mnt
>> 6) cd /mnt
>> 7) df -h .
>> Filesystem            Size  Used Avail Use% Mounted on
>> /dev/sda1              97G   90G  1.6G  99% /mnt/b
>> 8) Umount /mnt
>>
>> Hmm... this is not what I expected... I had assumed that somehow
>> the free disk space would somehow be reclaimed...
>>
>> What am I doing wrong here and how do I get around this?
>>     
> You have to resize Disk2 to 250Gb with resize2fs or parted.
>
>   

The answer is, you have to rezise after dd and there are two ways

1) e2fsck -f /dev/sdb; resize2fs /dev/sdb
2) Use gparted: a) shrink it down minimally, then regrow

Step 1 is faster, or so it seems