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-   -   how to install redhat on the attached external usb hard disk? (

hadimotamedi 07-24-2010 12:57 AM

how to install redhat on the attached external usb hard disk?
Dear All
I have RedHat Linux running on my VBox guest on my Windows host. I need to install RedHat Linux on the attached external usb hard disk ,connected to my guest machine.Can you please let me know how can install redhat on this external usb hard disk?
Thank you

Wim Sturkenboom 07-24-2010 02:19 AM

Just install it?

What you must be aware of is the location of the bootloader. If you use grub and install it in the MBR of your internal HD, your system will not be able to boot if the external HD is not connected (not even to Windows). Reason is that part of grub will be on the external HD.

No experience with this type of setup, so there might still be some catches that I'm [edit]NOT[/edit] aware off, but I see the following options to solve this:
  1. You can use LiLo instead on the internal HD (it fits completely in the MBR); not sure if RH still comes with LiLo (my experience goes back to RH8).
  2. you can install Grub on the external HD and use the bootsequence in the BIOS to determine what boots.
  3. you can create a boot partition on the internal HD and install Grub in MBR of the internal HD

hadimotamedi 07-24-2010 02:22 AM

Thank you for your reply.Can you please let me know how can I use 'dd' for this purpose ?

hadimotamedi 07-24-2010 02:31 AM

Can you please confirm if it can works this way ?
#dd if=/dev/hda of=/dev/sda

linuxlover.chaitanya 07-24-2010 03:52 AM

Why would you want to use dd for installation? It would clone the drive in my knowledge.

hadimotamedi 07-24-2010 04:19 AM

Actually, I need to make the same machine when connecting this usb hard disk to another machine. So I need some means of cloning my hard disk.Please comment me back.

linuxlover.chaitanya 07-24-2010 04:44 AM

If you want to clone the drive, then that dd command should do. But it would be better to use a cloning software like CloneZilla. It is a live distribution, hence both the source and destination drives would not be in use.

hadimotamedi 07-24-2010 07:18 AM

Thank you very much. It solved my problem.

linuxlover.chaitanya 07-24-2010 07:50 AM

If you elaborate on how you solved your problem, it could help other members coming for help. Also mark the thread as solved.

hadimotamedi 07-24-2010 11:07 PM

Sorry. My last question is if it is necessary that both of the hard disks have the same size for the 'dd if=/dev/hda of=/dev/sda' to be successful or they can have different sizes ?

hadimotamedi 07-25-2010 02:04 AM

I found that disk cloning is not suitable my case as the primary and usb disks are not the same size . Can you please let me know how to install redhat to external usb disk from the redhat installation cd ?

Wim Sturkenboom 07-25-2010 06:34 AM

The story continues in this thread where hadimotamedi tried to install on the external disk

saikee 07-25-2010 06:49 AM

First it is not necessary to go via a USB external hard disk if you can avoid it. Typically you can hook the second hard disk internally just for the cloning operation. An internal hard disk can be cloned between 3 to 5 times faster than an external hard disk via either a eSata or USB. Internal hard disk can transfer data between 45 to 85Mb/s but the speed will drop to 10 to 15 mb/s via a USB cable.

Secondly you can put the target disk in an external USB hard disk enclosure. On completion just remove the disk and use it to replace your internal hard disk or use it on another machine.

Thirdly you can dd a larger hard disk into a smaller hard disk as long as the partition table of the source disk you read from can be fitted into the capacity of the target disk you are writing onto. This means you might have to resize the partitions so that its overall footprint is no bigger than the target hard disk. Remember in cloning the resulting target disk must have exactly the same partition table as the source. If that partition table needs more cylinders than your target disk no operating system would touch your target disk!

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