A number of good replies already, but just to add a note:
I've been the maintainer of the g4l disk imaging project since 2004, and it
basically uses dd for most operations.
First thing, it will take a long time to do a clone of the disks.
Don't expect to get the speed that the drive reports, since that is the buffered
speed. In doing an clone image, the buffer is filled almost immediately, and
then you will be getting the physical speed.
On this machines I get the cached speed of about 100 times faster than the
physical speed. So, that is what you will probable end up getting for the
process.
hdparm -Tt /dev/sda
/dev/sda:
Timing cached reads: 6104 MB in 2.00 seconds = 3053.12 MB/sec
Timing buffered disk reads: 106 MB in 3.07 seconds = 34.53 MB/sec
As mentioned by others, the 2nd disk will need to be the same size or larger.
Sometimes the exact same disks can have different sizes because of bad
sectors. Had 20 new machines in classroom once, and drives all the same
make and model, but one system reported smaller size. Was able to image
that system to all the others with no issues.
dd_rescue is a good program if there are any bad sectors or problem
sectors, since it will try to work around them. It is included on the g4l disk.
I generally add g4l to the grub boot by using the 40_custom file.
Just copy the latest kernel and ramdisk.lzma file into the /boot directory
and then make a new grub.cfg file, and it is an option on boot.
Also, can be run from cd or usb.
# !/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries. Simply type
the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
menuentry G4L {
linux /bz4x18.5 root=/dev/ram0 telnetd=yes
initrd /ramdisk.lzma
}
menuentry G4L_NOSMP {
linux /bz4x18.5 root=/dev/ram0 telnetd=yes nosmp
initrd /ramdisk.lzma
}
menuentry G4L_FailSafe {
linux /bz4x18.5 root=/dev/ram0 noapic noacpi pnpbios=off acpi=off
pci=noacpi nosmp
initrd /ramdisk.lzma
}
Another issue that causes problems. If you make a clone image of the disks,
you should not reboot the machine with both disks, since they will report the
same blkids for the different disks since they are now identical.
In the past, it wasn't a problem, since one disk would be /dev/sda and the
other /dev/sdb, but most systems now use the blkid system, so have two
disks with the same ids causes issues.
Well, just some things to mention.
Good Luck.
On 6 Sep 2018 at 19:20, Ranjan Maitra wrote:
Date sent: Thu, 6 Sep 2018 19:20:37 -0500
From: Ranjan Maitra <maitra@xxxxxxxxx>
To: Community support for Fedora users
<users@xxxxxxxxxxxxxxxxxxxxxxx>
Subject: OT: fastest way to copy one drive to another
Organization: Mailbox Ignored
Send reply to: users@xxxxxxxxxxxxxxxxxxxxxxx
> Hi,
>
> I have two drives mounted on a F28 system. Both are identical 4TB drives. The second one is empty. I am concerned about the first one failing so would like to copy the contents (which are around 3.7 TB) to the second.
>
> What is the fastest way to copy the contents of the first drive to the second? I was using rsync, but is there a better way?
>
> Many thanks in advance for any advice,
> Ranjan
>
>
> --
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Guam - Where America's Day Begins
G4L Disk Imaging Project maintainer
http://sourceforge.net/projects/g4l/
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