# Formatting, partitioning, new external drive for Time Machine and Start up



## TuckerdogAVL (Jul 26, 2013)

Actually have a couple questions that may or may not relate. Just trying to wrap my head around it and maybe learn something new. And please let me know if I'm mixing apples and oranges. Spent some time online and on the web searching for answers and though there's a lot of info out there, I get deeper into confusion. 

Just got a new (replacement) external hard drive that I use Time Machine with. 

First, the formatting question. 
It's a terabyte. I need about 700gb for the back up (max as the drive in the computer is smaller than that) 

Question 1:
Can I partition part of the drive, to hold back, that won't be used for Time Machine? Or, does time machine like to not share a drive? 

Question 2: 
Formatting
If the first question is "yes, you can partition and just use part for time machine," can I use the other part as a place to put startup boot files for OSX in the event I ran into problems with OSX? I have a DVD of my OSX 10.6.8 and that's it. I've never had a back up of the operating system ever. Thought it might be a good idea. (And I haven't gone to 10.7 yet because I want to make sure all my programs (ie Office:Word 2008 for example, Adobe Cs4, Fission, etc ) will work in 10.7. 

Question 3: 
Do I just format as extended, journaled? Any reason to ever format as a GUID or any thing else? 

Question 4: 
And if the answer to 2 is yes, how would one boot up using the partitioned drive?


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## DeltaMac (Jul 26, 2013)

1. Yes - Time Machine (TM) works best with an extended (journaled) partition, which is generally the default, anyway.
about the size for the Time Machine partition: The figure that I often see is to use a partition for your TM that is a minimum of 2.5 times the size of the volume that you will be backing up. That will allow Time Machine sufficient space to work, and will give you a fair amount of backups before TM begins to delete the oldest backups.
And, yes, you COULD have a TM backup on a partition that's the same size as your hard drive, but then you would not be able to keep older versions of files, as TM would begin deleting the oldest files immediately (or stop working because you don't have enough space for more backups.)
I usually use a link here to Pondini's Time Machine FAQs, which will answer just about any question that you have about TM. http://pondini.org/TM/FAQ.html

2. Yes. Use your Disk Utility to set up as many partitions that you need. Go to the Partition tab (which you will only see when you select the line with the manufacturer's info in Disk Utility. For your simple case of one partition for Time Machine backups, and one partition that you can use to have a 10.6.8 boot system, you can select "2 Partitions" under the Partition Layout drop down. You can change the space used by each partition, by selecting each in the left hand column, then change the size, under Partition Information. You can name each partition, and you can also set each partition to have different formats, if you want. However, no need to do that, as both will be fine with MacOS Extended (journaled)

3. GUID (or the alternate Apple Partition Map) are NOT partition formats, but are the type of format (actually the partition map) for the drive itself, and is the format that the partitions are built on. The hard drive where you will install 10.6 MUST be partitioned GUID. You can set that when you partition the drive, by clicking on the Options button.

4. With your external drive partitioned the way that you like - boot to your Snow Leopard installer DVD, and choose the partition on your external drive (which you have set up for that purpose with several partitions!), and install OS X on that partition. That will result in a basic install of just the system. When that is complete, you can always boot to that external drive, by restarting your Mac, holding the Option key, and choosing that partition to boot. OR - you can change the booting system in your System Preferences/Startup Disk pane. That alternate system will always appear whenever you have the external hard drive attached.
BTW - I have a second bootable partition, which just has Snow Leopard fully installed, and up-to-date. It takes up about half of a 20GB partition.
So, if you don't want ALL your other stuff on that partition, and just the OS X system that you can boot to, and has a working Finder for copying files, or whatever else you need (I have a copy of Disk Warrior app on mine, and that's primarily what I use Snow Leopard for), you don't need a really large partition for a bootable system

5 (added!) And - you ALREADY have a backup of your operating system: your installer DVD. Safeguard it!


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## TuckerdogAVL (Jul 27, 2013)

THANKS SO MUCH for this thorough reply. Truly great information.


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## TuckerdogAVL (Jul 28, 2013)

> With your external drive partitioned the way that you like - boot to your Snow Leopard installer DVD, and choose the partition on your external drive (which you have set up for that purpose with several partitions!), and install OS X on that partition. That will result in a basic install of just the system.



Any suggestion as to how much space to allocate for the operating system (10.6.8)... and later, should I upgrade to Mountain Lion, will I be able to simply create the new boot disk by choosing this partition and it will overwrite just that portion and not the other partition for the time machine? Cool!


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## DeltaMac (Jul 28, 2013)

As I said in my post, I have a basic 10.6.8 (Snow Leopard) system installed on a 20 GB partition, and the operating system, as installed, takes up about 10GB of that space. If you anticipate booting to that system regularly, or will be installing other apps, then you should make the space larger. I think that 40-60 GB would be enough for any basic needs. And - you can upgrade to Mountain Lion from Snow Leopard at any time (through the App Store), or you could create a Mountain Lion installer on an 8GB flash drive, and upgrade the Snow Leopard partition, even without an internet connection. As part of the Mountain Lion install process, you would choose the destination for the ML install. Choosing your Snow Leopard partition would upgrade only that partition. (you would also get Mountain Lion's recovery partition as part of that ML upgrade install, added to the partitions on your external - again, without overwriting anything else)


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## TuckerdogAVL (Jul 28, 2013)

Thanks. Yes, see you did say that the first time. I partitioned it about 100gb so I'll make it a little smaller. However, weirdest thing. I'm getting the message that I've used 300+gb and I haven't done anything yet.


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## DeltaMac (Jul 28, 2013)

Looks like you didn't show the correct volume in your screen shot?  
That one shows that you have used about 650 MB out of 885 GB (which would essentially be an empty volume - you can't make a volume that uses NO space!)

If you have the second volume formatted for 100 GB, then that's probably OK on your 1TB drive. I just mentioned a small partition as one that would work - but it's also a good plan to have enough space for whatever else you might want to do with that system boot.


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## TuckerdogAVL (Jul 29, 2013)

No, that's it. That's what is weird. It should show nothing used. Nothing on it yet. The amount showing as "used" is about the size of what has been used on my hard drive 700gb/400+ used. I thought maybe it was showing up, maybe something to do with the journaling. 

Still a mystery. 

BTW, I reformatted to make the first partition about 60gb. Still show be ample. I'm not doing anything until I can figure out if I can get the old backup drive with all the old time machine mounted. It actually showed up a couple days ago (plugging in and out, turning on its side, upside down, etc), but disappeared again.


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## TuckerdogAVL (Jul 29, 2013)

1T. Partitioned into a smaller one and the larger one. Don't know where the two "used" amounts are coming from. Formatted as "Extended, Journaled" then partitioned. 

From Disk Utility: 




I don't know where the volumes/timemachine (MOUNT, at the bottom) is or comes from, or how it is derived, generated, etc. I didn't do it intentionally  

(doh).


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## DeltaMac (Jul 29, 2013)

?
If you use the Partition tab in your Disk Utility to create two partitions, then the default is to use the rest of the space to create the second partition, too!
How else do you think that second partition would be made? You did name both partitions, correct? 

Of course, it could still be a leftover from the original format for W-D. Did you apply the custom icons yourself?
If not, then the W-D firmware is the culprit, I suppose.


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## TuckerdogAVL (Jul 29, 2013)

DeltaMac said:


> ?
> If you use the Partition tab in your Disk Utility to create two partitions, then the default is to use the rest of the space to create the second partition, too!
> How else do you think that second partition would be made? You did name both partitions, correct?
> 
> ...



Never questioned how the space for the second partition is created. What I'm questioning is why it is showing that 200+ gb and 400+ gb have already been used when I haven't done anything yet? 

Yes, you can see from the "get info" pics that I named them. 

The WD external this is replacing, when I formatted it, showed a minimal amount of the 1T (like there was 997gb available) and "Zero" used. Wild.

I've run the "erase" twice and repartitioned, formatted, etc and the volume keeps showing up as existing and the drive with space "used"


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## DeltaMac (Jul 29, 2013)

But? ? ?
There's very little space used...
212 MB on one, and 650 MB on the other, larger partition. That's almost nothing, and certainly not the 200+ GB or 400+ GB that you mentioned! 
Are you misreading the units on space used? (AFAIK, there's still a considerable difference between MB, and GB  )


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## TuckerdogAVL (Jul 30, 2013)

DeltaMac said:


> But? ? ?
> There's very little space used...
> 212 MB on one, and 650 MB on the other, larger partition. That's almost nothing, and certainly not the 200+ GB or 400+ GB that you mentioned!
> Are you misreading the units on space used? (AFAIK, there's still a considerable difference between MB, and GB  )



YES. Absolutely. I am misreading it. Do'h... One of those things where you look and look at it and it takes someone else to say, "no....ah...." That clears it up for sure. Thanks again. That was making me crazy. 

PS It's like proofreading. I can't proof my own stuff; it always looks like the way I want it to.


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## DeltaMac (Jul 30, 2013)

I've been there, too!


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## TuckerdogAVL (Jul 30, 2013)

Closed to early. Some observations that I could use some comment on... before I do anything else. 

So, I connected the external, launched Snow Leopard (holding down the "C"), then installed the OS on the external in the partitioned sectioned I called "Start up." Okay, so far so good. 

I had to go through all the prompts about language, internet connection, keyboard (which is a MAC keyboard and it couldn't recognize it, just ironic), registration and when I hit "DONE" I was now started up from the external. 

Okay. I assumed as much. 

So, I restarted the computer, and it started up from the external. I didn't get a choice to choose the computer's OS system or the external. 

I shut down. 
Disconnected the external. 
Rebooted. Now I'm back on with the OS that is the computer's (There was a long pause with a white screen at the startup that was a little scary...  

So, I've reconnected the external and I see both the "start up" on the desktop and the other partition, "Time Machine BU." 
I'm going to restart now and see whether I get a choice or if the computer's OS starts me up. The reason being, that this is going to be the Time Machine BU external and if the computer can't go back and forth to sleep or restart without issue (or defaulting to startup with the external), I can't have the startup and time machine on the same external drive. 

Wish me luck!

PS I have diskwarrior as well. Can I launch it and install it on that startup section as well. You mentioned in the thread you had DW on yours.... Same process?


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## DeltaMac (Jul 30, 2013)

When your install OS X, the destination is automatically set as the default booting system. Change it to your internal drive (or whatever you choose) in your System Preferences/Startup Disk pane.
You can always choose another bootable partition by holding the Option key as the Mac restarts. Select the partition that you want to boot to, and you may have to press Enter to continue on with the boot.

You can copy your DiskWarrior app to your backup system. I usually copy it to Applications, or Applications/Utilities.
There's no installation with DiskWarrior, just copy the app itself to wherever you want to keep it.


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## TuckerdogAVL (Jul 31, 2013)

Thanks. When I reread your other post I saw your either/or, and I deduced the change to in System Preferences. Worked perfectly. Since I'm dedicating the partition to Time Machine, I'll load the Disk Warrior onto the partition I have labeled "Start up." I'm sure there is plenty of room. Again, thanks for all your help.

PS The Time Machine new backup finished so that's done. I guess I'll just reformat the other. I'll probably find I need something from a past backup in a couple days.


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