Re: dd to backup fat32 drive?
- From: Henrik Carlqvist <Henrik.Carlqvist@xxxxxxxxxxxx>
- Date: Mon, 16 Jan 2006 20:21:33 +0100
hazzmat <hazzmatunitedstatesgovernment@xxxxxxxxxxxxx> wrote:
> I saw something online about making a "dd" image of only the MBR-it
> involved strange blocksize and count arguments
> bs=? (I don't think it was 512) count=1,
Yes, it should be bs=512 count=1 to copy the MBR as the MBR is the first
512 bytes of your HD. The MBR contians some booting code and your
partition table.
> If I am going to dd the whole disk (/dev/hdc) shouldn't I make a
> partition of the same block count# that fdisk sees on the original
> laptop drive, on the new drive
If you do dd on the entire drive you will also copy the MBR and you will
get an identical copy of your partition table. Trying to alter that
partition table afterwards will most likely cause data loss as you also
would lose data if you alter the partition table on any disk with data.
> (which may not be identically sized overall?)
If the disk has a different size it also has a different geometry. (Number
of cylinders, heads and sectors).
> Also Is there any way to know ahead of time how likely a certain
> replacement disk is to work with the whole disk image approach?
It is probably hard to find anyone that can tell the likelyhood of this.
To get a feeling for likelyhood you need experience and in this case it
will take a lot of failures to get that experience. Most people probably
resort to another solution after a few failures.
> An identical model of drive could be in new old stock inventories
> probably --it would cost as much as a brand new but considerably larger
> drive I expect.
If you are going with the dd aproach it means that you are going to write
the old disks geometry data to the MBR and the partitions. This also means
that the new disk is going to look like it is as small as the old disk
was. To use the entire new disk you would need a partition table and
partitions with the correct geometry information.
> Would it help to buy the same manufacturer's model of the same time
> period but a different size?
I'm only guessing now, but maybe it would help if none of the values of
cylinders, heads or sectors are less than the corresponding value of the
old disk.
If I were you I would do the following:
1) Use dd to make a backup image of the entire old disk.
2) Use dd to also make backup images of each of the partitions on the old
disk.
At this point you have done all you can to save the data from the old disk.
3) Install the operating system on the new disk from the OS installation
media.
4) Install the applications on the new disk from the application
installation medias.
5) Do a "mount -o loop ro" of the partition images to restore data from
the old disk.
6) If the above 5 steps are not good enough you could experiment with dd
to restore to the new disk, but be prepared that the dd restore method
might fail.
regards Henrik
--
The address in the header is only to prevent spam. My real address is:
hc7(at)uthyres.com Examples of addresses which go to spammers:
root@xxxxxxxxxxxxx root@localhost
.
- Follow-Ups:
- Re: dd to backup fat32 drive?
- From: hazzmat
- Re: dd to backup fat32 drive?
- References:
- dd to backup fat32 drive?
- From: hazzmat
- Re: dd to backup fat32 drive?
- From: Henrik Carlqvist
- Re: dd to backup fat32 drive?
- From: hazzmat
- dd to backup fat32 drive?
- Prev by Date: Re: externel modem problem
- Next by Date: Re: externel modem problem
- Previous by thread: Re: dd to backup fat32 drive?
- Next by thread: Re: dd to backup fat32 drive?
- Index(es):
Relevant Pages
|
