I'm desperately trying to mirror a disk for backup purpose. The system is running on one IDE drive, and I want to make an exact mirror before an upgrade. I tried Symantec's Norton Ghost 2003 with terrible result.. The mirror didn't even boot. The system just displayed "GRUB" and nothing more happened. The 2 drives reports the exact same geometry to the system BIOS. Any ideas on how to accomplish my task? Anders Norrbring
drop to a prompt
dd if=/dev/hda1 of=/dev/hdb1
On Sat, 4 Sep 2004 03:49:58 +0200, Anders Norrbring
I'm desperately trying to mirror a disk for backup purpose. The system is running on one IDE drive, and I want to make an exact mirror before an upgrade.
I tried Symantec's Norton Ghost 2003 with terrible result.. The mirror didn't even boot. The system just displayed "GRUB" and nothing more happened.
The 2 drives reports the exact same geometry to the system BIOS.
Any ideas on how to accomplish my task?
Anders Norrbring
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mmarseglia writes:
drop to a prompt
dd if=/dev/hda1 of=/dev/hdb1
That will only copy the first partition, and assumes that the target disk is already fdisk'ed identically to the source, and has a valid boot block. Drop the "1" from both device names and you'll copy the entire disk. By default dd copies one 512 byte block at a time, which can be slow. By adding bs=64k it increases the copying per chunk to 64k bytes which should speed things up nicely. -Ti
Anders Norrbring writes:
I'm desperately trying to mirror a disk for backup purpose. The system is running on one IDE drive, and I want to make an exact mirror before an upgrade.
I tried Symantec's Norton Ghost 2003 with terrible result.. The mirror didn't even boot. The system just displayed "GRUB" and nothing more happened.
The 2 drives reports the exact same geometry to the system BIOS.
Any ideas on how to accomplish my task?
Anders Norrbring
If you simply want an exact byte-by-byte copy of your existing disk, go to single-user mode and then just do the following. (Assuming /dev/hda is the source disk and /dev/hdb is the target disk): dd if=/dev/hda of=/dev/hdb bs=64k This will copy *everything*, boot block, partition table, all partitions and filesystems, etc. Do this only in single-user mode so that you get a consistent copy (i.e., the filesystem isn't changing due to users and daemons at the same time you're copying). -Ti
Anders Norrbring writes:
I'm desperately trying to mirror a disk for backup purpose. The system is running on one IDE drive, and I want to make an exact mirror before an upgrade.
I tried Symantec's Norton Ghost 2003 with terrible result.. The mirror didn't even boot. The system just displayed "GRUB" and nothing more happened.
The 2 drives reports the exact same geometry to the system BIOS.
Any ideas on how to accomplish my task?
Anders Norrbring
If you simply want an exact byte-by-byte copy of your existing disk, go to single-user mode and then just do the following. (Assuming /dev/hda is the source disk and /dev/hdb is the target disk):
dd if=/dev/hda of=/dev/hdb bs=64k
This will copy *everything*, boot block, partition table, all partitions and filesystems, etc. Do this only in single-user mode so that you get a consistent copy (i.e., the filesystem isn't changing due to users and daemons at the same time you're copying).
Now that was just too easy and obvious to be a solution.. Geee, I'm stupid.. But why the 64k read/write limit? Anders
Anders Norrbring writes:
dd if=/dev/hda of=/dev/hdb bs=64k
This will copy *everything*, boot block, partition table, all partitions and filesystems, etc. Do this only in single-user mode so that you get a consistent copy (i.e., the filesystem isn't changing due to users and daemons at the same time you're copying).
Now that was just too easy and obvious to be a solution.. Geee, I'm stupid.. But why the 64k read/write limit?
64k is just something I pulled out of the hat. It's big enough to perform well, but not so big as to exceed hardware DMA transfer limits, which may cause the kernel driver to attempt to break up each transfer into smaller chunks, increasing CPU usage. -Ti
participants (3)
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Anders Norrbring
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mmarseglia
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ti@amb.org