How big a HD does Time Machine need?

MikeyTree

macrumors 6502
Original poster
Jan 5, 2007
295
0
I've looked for the answer to this, but haven't found it. How big a hard drive should I have for a time machine backup partition?

I have a 500 gig FW800 external hard drive, and want to partition it so it's not completely used up by time machine. My MBP's internal HD is effectively 125 gigs (160 gigs total, with 32 gigs used for Boot Camp). To back up those 125 gigs, how much external HD space should I allocate? 125 gigs? 250 gigs? Something in between?
 

aethelbert

macrumors 601
Jun 1, 2007
4,288
0
Chicago, IL, USA
It depends on many things:
1. How big your internal drive(s) is (or are)
2. How much you need to be backed up
3. How far in the past you want your backups to go

There are many other factors, and most users would be able to use 100GB. Heck, I'm only using 80 and that will be fine for me. Try 250GB, half and half.
 
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yetanotherdave

macrumors 68000
Apr 27, 2007
1,767
3
Bristol, England
to get a full backup is needs to be as big as the amount of data you have on your drive. To make sure you can always get a full backup of your drive it needs to be as big as your drive. To take advantage of incremental changes it needs to be bigger than your drive. Work out how much you need for the other stuff that you plan to put on the drive, and see what you are left with.
 
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chkdg8

macrumors 6502
Oct 24, 2007
250
0
I was wondering this as well. I'm researching a two external hard drive setup. One for Time Machine and the other for my media. My iMac came with a 320GB internal drive so should my Time Machine external drive be 320GB as well? The rest of my data will be movies, podcasts and pictures and that will go on a 1TB or 1.5TB external. Is this a recommended solution? I'm ready to buy but like I said, I'm researching reputable drives for my setup.
 
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motulist

macrumors 601
Dec 2, 2003
4,080
346
And remember, all the space on the drive that isn't consumed by the time machine backup data is still available as regular disk space. In other words, if your internal hard drive is 200 GB, and you only usually have around 100 GB of data on it, then if you get a 500 GB external time machine drive you'll wind up with 400 GB of extra storage space to use for whatever. Of course the extra material stored on the external drive won't be backed up, but if you have large files that you don't care about losing, like torrented tv shows or whatever, then it works out fine.

So really it all depends on how much data you plan to back up, how far back you want the time machine archive to stretch back, and if you have large files that you don't care about backing up.
 
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DoFoT9

macrumors P6
Jun 11, 2007
17,530
33
Singapore
for a light user i normally recommend getting a drive that is roughly the same size of the hard drive they are backing up. for medium-heavy users 1.5x-2x is recommended.
 
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motulist

macrumors 601
Dec 2, 2003
4,080
346
My iMac came with a 320GB internal drive so should my Time Machine external drive be 320GB as well?
It doesn't matter how big your main drive actually is, it only matters how many gigs of actual stored data you want to back up, and how far back in time you want multiple versions of each file to be archived as. So if you have a 320 GB main drive, but only ever have about 100 GB of data used on it, then your backup drive only needs to be 100 GB + extra space, rather than 320 GB + extra.

The rest of my data will be movies, podcasts and pictures and that will go on a 1TB or 1.5TB external. Is this a recommended solution?
The extra space that isn't consumed by the time machine backup data is still available for regular storage. So your media storage and time machine backup can be on the same external disk drive.


I'm ready to buy but like I said, I'm researching reputable drives for my setup.
I highly suggest Western Digital.
 
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chkdg8

macrumors 6502
Oct 24, 2007
250
0
Thank you motulist for your great advice. I'm taking your suggestions very seriously now that my questions were answered. WD is highly recommended but I just ran into this 1TB Lacie drive over at newegg just for my video. Not bad for the price either. With that being said, some users on here still suggest a second hdd just for back ups. If I decide to go that route, is a small (under 500 GB) USB 2.0 external still worth it? That Lacie has some good writing and transfer speeds for my HD content which is great for my media center but my concerns are more towards my personal data.
 
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chkdg8

macrumors 6502
Oct 24, 2007
250
0
from the bottom of my heart and my recommendations... DO NOT GO WITH LACIE!!

you are not guaranteed quality!
I keep hearing that but the reviews are mixed. Although I'll give it to you that the bad reviews are more than good.
 
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DoFoT9

macrumors P6
Jun 11, 2007
17,530
33
Singapore
I keep hearing that but the reviews are mixed. Although I'll give it to you that the bad reviews are more than good.
my main concern is that you dont know what brand of HD you will get, they buy whoever is the cheapest or has the most units. their hardware quality is fine, though!
 
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