> Oh, I thought that by "image" you meant like Ghost makes under Windows, or
> like "cat /dev/hda > file" would make. You meant duplicate the drive.
> Right, that'll work. That's basically what I'm doing now.
Last I checked, Ghost makes an exact duplicate that doesn't have any
additional overhead on the destination media. I suppose I could be
mistaken.
> Something must be wrong, though -- CPU use rises to ~50% during the copy.
> Both drives use DMA, according to hdparm. I didn't think CPU was supposed
> to be used during a DMA transfer.
Copying uses processing power because the processor is making decisions to
manage reading and writing. DMA only allows other devices to directly
access data from the drives without having to go through the processor.
Something still needs to control the drives, and if there aren't any
additional devices doing so that task falls to the CPU.
> Run "gzip -f" where it reads from /dev/hda, and writes to
> /backup_drive/image.gz . "gzip -f" gives fast, low-quality compression.
> It's equivalent to "gzip -1". I would use "compress", but that's not
> installed by default in many distributions.
Thanks for the clarification.
> If I had a DVD burner, I might consider backing up to DVD-RW, but hard
> drives are getting bigger, and DVD media is getting cheaper, and I don't
> know which is doing it faster. Right now, 115GB/4.7GB~=25 DVD-RWs,
> best price that I could find in a cursory search is $110 for a spindle of
> 25 DVD-RWs.
I'm not terribly enthused about DVD-RW technology yet, anyway. The standard
is in far too much flux right now.
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