Using dd to copy a filesystem

[Bill Costigan]

I would like to use dd to copy a filesystem from one lvol to another.

Will this work and should I use the raw or cooked lvol?

e.g.

dd if=/dev/vg03/rlvol3 of=/dev/vg04/rlvol3 bs=1024K

Thank you in advance.

[A. Clay Stephenson · Accepted solution]

As long as the destination LVOL is at least as large as the source that will work just fine --- and yes, you want the raw (character) device nodes. The filesystem should be unmounted before the dd is run.

[James R. Ferguson]

Hi Bill:

Use the raw filesystem and a large blocksize as you have shown for the best performance. There is no sense to invoking the buffer cache by using the cooked device files.

The source and target filesystems should not be mounted during the copy and an 'fsck' afterwards is advisable.

Regards!

...JRF...

[Bill Costigan]

Thank you both!