# ideal hd size for time machine



## BobbyFett (Jan 12, 2005)

i've got a 250gb hd hooked up to my 250gb hd imac... i've about 100gb left on my internal drive... 

time machine is currently only giving me about 3 days worth of back up.

what's an ideal capacity for this kind of size hd? obviously, the bigger the hd, the longer the backup period... but right now i'm not getting much chance for realising i deleted something...

i suppose the only stuff i should have time machine back up is my stuff right? no sense in backing up my applications folder etc right?


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## Iwantamac (Sep 25, 2006)

The glib answer is the "the bigger the better". I picked up a LaCie 500Gb drive for $129 from Future Shop to back-up about 80 Gb (from a 250 Gb HD). I'm also using a 250Gb Beyond Micro drive for Super Duper so that I have a "bootable" back-up - call me paranoid.

iMac 24 2Gb, 250 Gb HD,NVIDIA GeForce 7600 GT
Apple Airport Extreme, Apple Airport.
iPod Classic 80Gb
iPod Nano 1Gb
Canon i850, Lide 600F
Elgato eye TV Hybrid


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## dona83 (Jun 26, 2005)

Your Time Machine back up drive should be about double your internal drive being backed up..


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## MacDoc (Nov 3, 2001)

There is no ideal - the bigger the longer the way back machine works is all.

We do recommend tho a big enough drive that one partition is used for a bootable clone and the rest for TM just for your user folder(s) sans application folder.
Space goes much further.


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## chas_m (Dec 2, 2007)

BobbyFett said:


> i suppose the only stuff i should have time machine back up is my stuff right? no sense in backing up my applications folder etc right?


If you have no third-party apps (or have other backups for them) then you're right, just backing up your User (Home) folder would free up enormous amounts of space on the backup drive and allow Time Machine to go much further back in time.

Most people, though, want a complete and utterly identical backup, so the prevailing advice of "get a huge-ass hard drive" is probably best, particularly given that HDs are very cheap these days. 1TB drives can be had for around $250 if you shop around. Don't know that I trust these yet myself, but even a 500GB MyBook Premium is IMHO a very attractive deal for around $139 at Costco.


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## eMacMan (Nov 27, 2006)

chas_m said:


> If you have no third-party apps (or have other backups for them) then you're right, just backing up your User (Home) folder would free up enormous amounts of space on the backup drive and allow Time Machine to go much further back in time.
> 
> Most people, though, want a complete and utterly identical backup, so the prevailing advice of "get a huge-ass hard drive" is probably best, particularly given that HDs are very cheap these days. 1TB drives can be had for around $250 if you shop around. Don't know that I trust these yet myself, but even a 500GB MyBook Premium is IMHO a very attractive deal for around $139 at Costco.


Even with the third party apps, full back-up is only essential when you make changes to the system. Personally I back up entire OSX maybe once every other month and back-up crucial files once or twice a week. However I am in the habit of doing a string of Save-As'es when I am making a lot of changes and might want to go back to a former life.


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## spoonie (Nov 25, 2007)

my TM drive is 2x the size of my boot volume.


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## jasonwood (Oct 19, 2003)

I would think 250GB should be good for backing up 150GB of data for a lot more than 3 days, but I suppose an exception would be if you work with very large files, as every small change to a large file results in another copy of that file being backed up. Editing video maybe?


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