Time Machine

this is from both MacFriar and myself.

We were chatting by email earlier this evening and he has a problem with Time Machine.

How do I partition the external HD for a back up? Time machine wants to completely wipe the drive off. That is crazy since it is a 250GB drive and my HD is only 80GB.

I sent over the instructions re partitioning [ I've done it twice now :) ] and got this back

No can do. All my external HDs have important stuff on them. I guess I will have the machine on and take a chance of losing the data.

have reminded him that TM backs up till there is no more space and then it deletes the oldest and starts again.

Then he decided to look and see if he could make a 100GB partition for TM but seemingly this is not possible without wiping the drive

After that he had to go out to an evening meeting but said

I just checked. Outside of programs, I have only about 4gb of files on the machine. I have a spare dongle so will back it up to that

dunno what size his dongle is .

Now can anyone tell us how to partition an external drive that has lots of stuff on it that he can't shift elsewhere ?

Disc utility lets you partition non-destructively in Leopard I think.

You go to Partition tab.

There wil be an image of the drive with dat grey and free space white.
There is a handle bottom right. Drag that up close to the data.

Clikc the + sign and a new partition fills the white space (called discname_2), which you can format. Click on the other partition and the nots say it will not be wiped.

All of the following relates to Leopard. [Edit - and was cross posted with the far more succinct responses above!]

1. Time Machine can share a partition with other data. The bad news is that it will expand to fill all of the free space on the partition it is on, so your free space for the other data will gradually disappear.

2. Disk Utility *can* partition a disk that already has data on it without deleting that data.

When you select a drive in the left column of Disk Utility (not an indented volume - the complete drive) you can select Partition in the tab set. You will then see an image showing the current arrangement for that disk. Each partition/volume will be shaded pale blue to show the amount of space used, and the rest of it will be white.

The instructions in the window are in two sentences, defining two very different options:

- "To erase and partition the selected disk, choose a volume scheme, set options for each volume, and click Apply". You don't want to do that if you have data you want to keep.

- "To resize the volumes on the selected disk, drag the dividers between them and click Apply". This option does NOT erase the disk.

So ...

Don't try changing the drop down menu for Volume Scheme, as that always erases the disk to create a new scheme.

Just drag the little shaded corner at bottom right of any existing partition up to reduce the size of the available space. Disk Utility will not allow you to reduce it below zero. When you have created a large enough grey space in the 'map' you can then click the '+' button to create a new partition to fill that space.

All of this can be done non-destructively, and the words at the side of the diagram should tell you that the selected volume would not be erased to achieve the changes you have set up. You can Revert at any time in this mode. Once you have a partition scheme that you want, hit Apply to make it happen.

Hope this helps.

Edited by deleted (Wed 18-Mar-09 23:10:49)

That's much more thorough .

The key is DON'T use the partition drop-down menu at the top of the map. Use the + button at the bottom after you have created the space.

HOOORAY

THANKS GUYS

I thought this was possible - the link has been sent to MacFriar so he can amuse himself later and get his external drive set up .

Let us know how it goes - in case we need to hire lawyers

so far it hasn't - he's still not convinced it can be done without wiping the external Hard Drive and he absolutely cannot afford to lose anything he has parked there [ umm .... backed up to there ]

He also says he can't afford to buy another external drive at present.

He's also very short of time due to a problem with his MacBook which is going to Cupertino today - all this 'blew up ' yesterday.

We [ him or me :) ] will keep you updated

I may experiment since my 500GB external only has 2 partitions at present so I'll see if I can add a third - it won't be a disaster if it doesn't work since the wee portable external has everything on it

One thing I read somewhere - I think you cannot change the starting point of a partition. so you need to add a new one after the last one, shrinking that to make room.

A very wise man. It is sensible to never do a potentially destructive operation, such as resizing a partition without first having a backup of any irreplaceable data. (Indeed, if the data is irreplaceable you should have a backup of it anyway. Hard disks have been known to fail.)

No DVD writer? Blank DVDs are very cheap. Mind, hard disks aren't too pricey nowadays.

I've resized partitions many times and have only destroyed data on a couple of occasions - but two is two too many (and, yes, I did have backups of any important data).

I'm probably wrong, but can't you set up Time Machine on an existing partition? What about using something like CarbonCopy to clone the disk? You could always create a disk image on the hard drive, to keep things neat, rather than using it directly.

Edit: Just re-read your OP where you say that Time Machine insists on wiping the destination partition. In that case, create a Disk Image on the external drive, of an appropriate size, and use that for the destination disk in either Time Machine or Carbon Copy Cloner. That way there is no scary messing with existing partitions.

Edited by deleted (Thu 19-Mar-09 13:15:19)