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Time Machine and External Drives

I

iBecks

macrumors 6502
Original poster
Nov 24, 2006
406
6
Nottingham, UK
The store was quite busy on Friday evening, most were buying Leopard and an external hard drive.

Time machine is pushing these external drive sales.

What would be an adequate size hard drive for Time Machine?
 
what would be a good hard drive around the 100-150 or so range. i have 120gb on my macbook with about 35gb left but i want to take advantage of time machine. or am i going to have to make a little but larger of an investment
 
the best deal i have seen is a LaCie (spelling?) 500gb drive on Newegg.com for about $115. I'm considering purchasing one for myself to replace the 160gb drive i'm using now.
 
RumMunkey said:
then you need a minimum 160 GB external. Maximum will be the absolute most you can afford.
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You don't really. For instance without my iTunes stuff I have about 30 GB of total data on my main 500 GB drive. If it wasn't for iTunes a 50 GB drive would probably be sufficient. Your Time Machine hard drive doesn't need to be as big as your main hard drive, only as big as the files you want to back up. Granted if I have a 500GB hard drive for Time Machine (which I do) I will be able to retrieve files from 10 years ago probably (in the future!) but at that point the files aren't really deleted, they're forgotten.

Your external hard drive should be as big as the files you need to back up at least and then some more to be able to go back a few months if need be. Time Machine will keep old files you delete/change so if you are changing/deleting small files all the time your extra space doesn't need to be large. If you are daily changing 100 MB photoshop documents a larger hard drive is probably needed. While music/movie files may be large, they don't change often so odds are Time Machine will only have one copy of this file in its archive. You need to take into consideration the files you will be changing often when determining how much space you need.

It's not a bad idea to get a drive at least as big as your current drive but that is by no means a minimum. I would say at minimum you should get one either the same size as your main drive or one that is twice as big as the amount of disk space you are using.
 
As my music and photos are on my iPod, which is effectively a backup, then I am only looking at documents and maybe my vhd files.

I mention vhd files, these would change each time I exit the Virtual Machine, therefore they may get backed up multiple times per day, taking up a lot of space.

Maybe I should backup the whole user folder!

I think I'll go for a 500GB drive and be selective on my backup choices.
 
Does Time Machine require the entire external hard disk, or can I still use the hard disk for other stuff?
 
ICEBreaker said:
Does Time Machine require the entire external hard disk, or can I still use the hard disk for other stuff?
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No it does not require the whole disk. You can have other data on it also. Keep in mind the more data you put on it, the smaller amount of files time machine can keep.

iBecks said:
I mention vhd files, these would change each time I exit the Virtual Machine, therefore they may get backed up multiple times per day, taking up a lot of space.
Click to expand...

I wouldn't back them up with Time Machine. That will take a ridiculous amount of space and before you know it Time Machine will start dumping old files in favor of newer ones. If you can, keep backups of your VM's at certain points manually (initial install, after installing all your programs, etc) and try to keep data on a separate partition that Time Machine can back up. This way you can retrieve old files instead of old VM's which you probably don't need.
 
SilentPanda said:
If you can, keep backups of your VM's at certain points manually (initial install, after installing all your programs, etc) and try to keep data on a separate partition that Time Machine can back up. This way you can retrieve old files instead of old VM's which you probably don't need.
Click to expand...


Good advice, I do keep my data within OS X and access it through networking on each vhd.

I'll not bother with continuous Time Machine backups of the vhd's themselves.
 
Clueless newbie follow-on question

I'm about to switch over from a PC to an iMac. I have a practical question about time machine...

Currently, my ultra-paranoid backup strategy (on my PC) is to use two identical external USB drives. One lives at home; one lives at work (for potential disaster recovery).

I backup my files the entire month. At the end of the month, I disconnect which ever drive I have at home, take it to work, bring the work drive home, connect it, then use that drive for the next month's worth of backup.

What I like about this approach, is that maximum amount of data at risk (ever) is 30 days.

So my question is, will time machine and two external drives support this approach? Will time machine happily let me swap external drives monthly?

I mean having a local backup drive is all fine and good... unless your house burns down (don't laugh, I live in Southern California - about 1,000 folks found out first hand how real that concern should be for everyone).

Thanks in advance.
 
Your work/home scenario should work. When you plug the "new" drive in you'll just need to tell Time Machine to use the new drive. It will then see you haven't backed up in a month and start backing up all new stuff.

So yes, you'll just have to configure it every month.
 
Thanks Panda... one more...

So once TM "knows" each drive, I shouldn't have to configure EACH month, right? Just once per drive?

I intend to make the externals full mirrors of the internals so that I can boot from them if need be.

SilentPanda said:
Your work/home scenario should work. When you plug the "new" drive in you'll just need to tell Time Machine to use the new drive. It will then see you haven't backed up in a month and start backing up all new stuff.

So yes, you'll just have to configure it every month.
Click to expand...
 
ToneMonkey said:
So once TM "knows" each drive, I shouldn't have to configure EACH month, right? Just once per drive?

I intend to make the externals full mirrors of the internals so that I can boot from them if need be.
Click to expand...

No. Time Machine only works with one drive. When you pull out the drive it's configured for, Time Machine stops working until you tell it a new drive or put the old drive back.

You'll have to go in each month and say, "Use this drive." But that should be all.
 
Fair enough... is TM smart enough to...

Beginning with the third month, I'll likely be reattaching an external drive with lots of unchanged content (my day job is actually in the backup/restore space and I know that changed content on any desktop client is typically <1MB/day and the OS stuff hardly changes at all). Will TM know which stuff on the external drive is identical to the internal drive? Otherwise, moving all 300-400GB of my internal drive data at the beginning of each month could take quite a bit of time. Days? I've been using SmartSync Pro on Windows, which is aware of unchanged files and doesn't bother resending them.

Many thanks for the detailed and knowledable replies.

SilentPanda said:
No. Time Machine only works with one drive. When you pull out the drive it's configured for, Time Machine stops working until you tell it a new drive or put the old drive back.

You'll have to go in each month and say, "Use this drive." But that should be all.
Click to expand...
 
I actually am not sure. I would hope so but I haven't tested it.

You may want to consider a program such as "SuperDuper!". I know it will do what you want and it's $30. It will let you clone a drive doing a smart update. The only difference is you won't be able to retrieve old version of files as you go.
 
ToneMonkey said:
Beginning with the third month, I'll likely be reattaching an external drive with lots of unchanged content (my day job is actually in the backup/restore space and I know that changed content on any desktop client is typically <1MB/day and the OS stuff hardly changes at all). Will TM know which stuff on the external drive is identical to the internal drive? Otherwise, moving all 300-400GB of my internal drive data at the beginning of each month could take quite a bit of time. Days? I've been using SmartSync Pro on Windows, which is aware of unchanged files and doesn't bother resending them.

Many thanks for the detailed and knowledable replies.
Click to expand...

I'd say a better strategy would be to use Time Machine only on the backup drive you keep locally, for file recovery and whatnot, and just continue to do a monthly backup with Deja Vu or SuperDuper or CarbonCopyCloner (or whatever you use now) to keep off-site.
 
killmoms said:
I'd say a better strategy would be to use Time Machine only on the backup drive you keep locally, for file recovery and whatnot, and just continue to do a monthly backup with Deja Vu or SuperDuper or CarbonCopyCloner (or whatever you use now) to keep off-site.
Click to expand...

I'd have to agree. That sounds like a good plan, may I recommend using rsync— in my limited testing arRsync seems like a nice implementation of it. I used to rsync in a backup script fired by cron every day, it worked like a charm. My first use was through the GUI rsyncX, but I think that is a dead project these days. At anyrate rsync does what you are looking for in terms of updating only changed files — it can also do a lot more like exclude directories, ignore files you've deleted from the source, and backup over ssh to name a few. Best of all, it's already built into your computer.
 
maninthemoon said:
I've been looking at those drives also. You can get the 250GB version for only $5 more. Or you can get the OWC on-the-go 160GB portable drive for a similar price.
Click to expand...

i didn't even notice that. i guess it would be worth it for five more bucks and 90 more gigs but i still want to know if these are good drives and what people think of them!
 
i bought an iomega external HD (500GB for 99 bucks CAD. can t complain about the price) i do not know how good it is quality wise but it s been very good since i bought it two days ago, i Partitioned it in two half for time machine half for whatever i want the space for now, there s one thing i do not understand, i 've been letting TM do it s thing but now it says i only have 19GBs left of the 233GB i had in there for it? what? that's insane.... does this mean that i am only ever going to be backing up my stuff for like a couple of days at a time and TM is going to get rid of everything else after a couple of days? doesn't sound right to me... anyone knows what is going on here?by teh way my internal is only 80 GB
 

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Is it backing up your other partition on your external or any other external drive? Perhaps a mounted network drive? Check in the options to make sure your not backing up that stuff.
 
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