Linux RHEL : Making disk image efficiently
- by TheProfoundGeek
I have a linux box having RHEL. Its disk (hda1) is having free space of about 25GB.
I have an another disk (hda2) which is of 250GB having another RHEL instance, it's partitioned for 200GB. Data on the disk occupies about 21GB of data.
The image of hda2 needs to be taken and restored on other disk of same specs. What is the best way to make image file of the hda2?
Ideally the images size should be around 25GBs as the actual data on the disk is just 21GB.
I am aware about the following two methods.
Method 1 : Raw Image
dd if=/dev/hda2 of=/path/to/image
dd if=/path/to/image of=/dev/hda3
Question 1 : Will the above method make a gigantic image of 250GBs? Is it efficient?
Method 2 : Compressed Image.
dd if=/dev/hda2 | gzip > /path/to/image.gz
gzip -dc /path/to/image.gz | dd of=/dev/hda2
Question 2 : I tried the method 2, its taking too long. What are the pit falls of this methods?
Which of the above method id efficient and why? Is there any other Linux utility which can do the job? Third party tools are no no.
