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)

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.

It's true that you can't move the start of an existing partition. However, you can create new partitions in gaps you create between or after the existing partitions. A new partition doesn't have to be at the end if the biggest gap you can create is somewhere in the middle.

It's easy to experiment to see what's possible. You can Revert any changes you make to the partition map, and nothing actually happens as long as you don't hit Apply.

I have ried this on my external and all worked fine. However I don't think I'd risk it if there were un-losable data on it.

well - I'll be experimenting later today since I have back ups on both my external drives

My 320GB drive has 3 partitions - SuperDuper , TM and a , at presently , unused one . This is the external Drive that will come on holiday with me.

My 500GB just has 2 partitions - SuperDuper and TM This is the stay-at-home external - so as there is masses of room on it I'll experiment on this one

Maybe two successes will give MacFriar enough confidence.

he has confidence - just didn't have the time

To back up his MacBook and iMac to DVD disks would take between 12 and 25 DVDs and he did not have that number at home . And just think how long it would take to do that lot

He does have a lot of stuff that he uses for work - and couldn't risk any catastrophes .

Once things are back to 'normal [ hehehehehe] I'm sure he will get things straight so he doesn't get in this situation again.

Oh - and I gather that neither of his externals are partitioned .

Folk laugh at my back ups - but if one external Drive goes - I still have the other so all is not lost.

Edited by goldenoldie (Thu 19-Mar-09 15:33:46)

In reply to a post by goldenoldie:

Folk laugh at my back ups.....

With apologies to Confucious, "He who laughs at anothers back up will fall from tree and break head."

He could have also created a 100GB fixed size disk image and used that for time machine.

True - but that's being wise AFTER the event.

He was backed up - all his work related stuff was OK - it's just that there were things on the Hard Drive that he didn't want to lose , and he hadn't time to change his systems for this

I'm not sure if I misunderstand the situation, but creating a disk image wouldn't have involved changing the external hard drive in any way - just creating a file on it. True it would have taken an hour or so to create the backup.

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.

Sorry to resurrect this, but I've just implemented TM for the first time and on the both the drives (two computers) it is being used it did not want to wipe the drive (I did a lot of faffing to make sure important files were safe only to find it was largely unnecessary).

TM created a folder with the backups in.

As I wrote on 18 March:

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.

Options are to repartition it non-destructively as discussed, or to create a disk image on the disk that will not expand beyond its defined size.

Of course!

I tried to partition the old ext drive (hence the faffing) but it wouldn't let me, I guess because (at a guess) it was too fragmented - the old "Not enough Free space" error. Know a good free defragger?

In reply to a post by ian_c:

Of course!

Know a good free defragger?

Most of them seem to be paid apps like TechTool. There's a free version of one, but it's limited to 100MB partitions, I believe. Simplest I've seen is to Carbon Copy Clone the partition to another location, reformat, then CCC it back again. But that isn't really what you're looking for.

Ah well.

The only files on te disk are my totallylegitimatedownloads. If I lose them it is a pain, but no great tragedy.