how to use dd to backup second linux hard drive from os x?

Question

I have a MacBook with Linux installed on the primary hard drive. On an external USB 3.0 drive, I have OS X installed.

The external drive has plenty of space so I would like to boot up OS X and make regular copies of the primary drive using dd.

Performing the backup the other way would be simply done using something like: dd if=/dev/sda of=/backups/backup.dmp, however, OS X is a little alien to me, so I'm not sure how to reference the primary drive from OS X.

What would be the dd command line for making a backup?
What would be the dd command line for restoring the backup?

note that you don't actually need dd for this. – strugee Jul 01 '15 at 19:08 — strugee, Jul 01 '15 at 19:08

score 1 · Accepted Answer · answered Jul 01 '15 at 18:22

1

diskutil list

will show you the Drives.

A Partition is /dev/diskXsY.

So

dd if=/dev/diskXsY of=/BACKUPIMAGE.img

with the appropriate X and Y should do it for you.

answered Jul 01 '15 at 18:22

Jodka Lemon

3,173

I would like to backup the whole disk, so I guess it will be dd if=/dev/diskX of=/BACKUPIMAGE.img? – Chris Snow Jul 01 '15 at 18:39
Yes, I think so. Maybe a bs=4M or so, to make it faster. – Jodka Lemon Jul 01 '15 at 18:48

how to use dd to backup second linux hard drive from os x?

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