$ sudo dd of=/dev/disk2 if=/Users/mike/diskimage.img bs=64k ⇐ copy image to diskġ20040980480 bytes transferred in 3474.Here's a quirk: Last week, I ran into a corollary issue: while I have been able to read files from Mac external USB HDs, I found recently that I was unable to WRITE to any of the ones I tried! The user number was 99, and since I know Mac OSX is in fact a Unix variant I tried creating a user with user number 99. $ diskutil list /dev/disk2 (external, physical): The dd command is almost the same, but if and of are reversed. You also need enough local disk space for the image.Īnother option, if you can concurrently attach both disks, it to copy directly: sudo dd if=/dev/disk2 of=/dev/disk3 bs=64k This will take a long time, and there is no progress bar. Unmount of all volumes on disk2 was successful $ diskutil unmountDisk /dev/disk2 ⇐ unmount the source disk $ diskutil list ⇐ list attached disks and partitions /dev/disk2 (external, physical):Ġ: FDisk_partition_scheme *120.0 GB disk2 Open Terminal, identify the disk and unmount it: If the following warning appears, click Ignore: You can use this procedure with any drive: eq, to clone an MGC Compact Flash from one with a known password.
If the copy fails due to disk errors, try using the following command at step 3:ĭd if=/dev/disk2 of=/Users/mike/diskimage.img conv=noerror,syncĭd will take much longer using this option, errors are written as NUL bytes. The second dd command is almost the same, but if and of are reversed. Sudo dd of=/dev/disk2 if=/Users/mike/diskimage.img Attach and identify the destination disk ⇒Ħ. Sudo dd if=/dev/disk2 of=/Users/mike/diskimage.imgĤ. If the installation has primary and backup signalling servers, clone one at a time to avoid service interruption. Make a working copy of a Signalling Server hard disk This option can often recover a dead hard drive, or an unreadable file, but it does not repair the error. If the operation stops with an I/O error, try to salvage all readable data with conv=noerror,sync. conv=noerror,sync tells dd to be fault-tolerant and ignore read errors (optional).bs=n sets both input and output block size (optional, default=512 byte blocks).of= specifies output path (file, or device).if= specifies input path (file, or device).
There's also a freeware version of dd for Windows available, with instructions.
How to clone a hard disk or USB stick in the terminal.ĭd (disk duplication) is a Mac OS X command-line utility which can read raw data off a disk, even if the Mac doesn't understand the filesystem.