Raid mirror question

[Julianne]

hi,

I was wanting to set up raid mirror in panther and do both drives have to be empty and formated with the same file system? The thing is I have a 250gb ntfs drive that I want to back up to a 250gb hfs drive. The hfs drive is empty but the ntfs drive is full of data I don't want to loose.

Any help welcomed!

 

[Bear]

hi,

I was wanting to set up raid mirror in panther and do both drives have to be empty and formated with the same file system? The thing is I have a 250gb ntfs drive that I want to back up to a 250gb hfs drive. The hfs drive is empty but the ntfs drive is full of data I don't want to loose.

Any help welcomed!

A backup is different from a RAID mirror. A mirror is when both drives are constantly kept up to date. A backup is a static snapshot of your data.

So it sounds like you don't want to mirror your drive.

Now to answer your original question. Since both drives in a mirror set are copies of each, they do have to be the same file system since they are identical copies of each other. With Apple, I'm not sure if you can mirror a drive once it has data on it. I know with some other operating systems, you can do that.

 

[Makosuke]

I assume what Julianne wanted to do was use her currently empty disk plus the NTFS disk to create a single HFS+ RAID volume with the data from the NTFS disk. Ideally, this would involve copying the data from the NTFS disk to the HFS+ one, then just telling the OS to add the formerly NTFS disk as a mirror of the HFS+ one that now contains the data. Using at least some RAID tools, that's possible, but as with Bear, I'm not sure that with Apple's built-in tools you can mirror an existing disc to a new one, or if you have to create the RAID set from scratch and then copy data to it.

In either case, you're going to need to eventually reformat the NTFS disk, since Apple's RAID of course requires both disks to be in the same format and can't RAID an NTFS volume.

Looking through the Disk Utility help files, it does sound like you might be able to mirror an existing disk, though. You could copy everything to the HFS+ disk and see if you can add a mirror to it, but you want to be careful you don't accidentally reformat both disks in the process.

Hopefully someone who's tried it will reply.