Node cloning

Felix Rauch rauch at
Thu Apr 5 09:43:39 PDT 2001

On Thu, 5 Apr 2001, Oscar Roberto [iso-8859-1] López Bonilla wrote:
> Configure ONE slave node
> Install the configured hard drive on /dev/hda
> Install three hard drives on hdb, hdc, and hdd
> And then use the command (this will take long, so you can do it overnight)
>          cp /dev/hda /dev/hdb ; cp /dev/hda /dev/hdc ; cp /dev/hda /dev/hdd

I never used cp to clone partitions. Usually I use "dd":

  dd if=/dev/hda of=/dev/hdb

Note that for UDMA IDE drives you can turn on the DMA to speed things
up (use hdparm). With the most recent kernels this is probably no
longer needed or you can configure it right in the kernel.

You could probably even speed up things a bit by starting your above
three commands in parallel. If caching works to your advantage, then
the data needs to be read only once from /dev/hda. OTOH, if the drives
b, c and d are not in sync, then things might get much worse as the
a-drive starts thrashing.

- Felix
Felix Rauch                      | Email: rauch at
Institute for Computer Systems   | Homepage:
ETH Zentrum / RZ H18             | Phone: ++41 1 632 7489
CH - 8092 Zuerich / Switzerland  | Fax:   ++41 1 632 1307

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