What size backup drive for time machine on 500gb MBP?

I'm sure this is a really novice question, but I couldn't find the answer on the forum.
I've just got a MBP with a 500gb HDD. I won't be buying a Time Capsule, but I'd like to set up Time Machine to backup to an external USB HDD. What is the optimum size for this?
I see that time machine keeps deleted files, I'm not sure if it uses compression, and I'm not sure what happens when I run out of space... does it reduce the number of duplicates that it keeps, or will I run into a problem?
Really, what I'm trying to find out is: I have an old 500gb HDD that isn't being used for much. Is this sufficient to back up a 500gb HDD (assuming that, at some point, I'm going to be hovering around maximum capacity on the MBP)?
Thankyou!

Hi and welcome to Discussions,
our local Time Machine 'Guru' Pondini has made a very thorough FAQ on it to be found here http://discussions.apple.com/thread.jspa?threadID=1964018
Quoted from it (section 1):
"A general "rule of thumb" is, TM needs 2 to 3 times as much space as the data it's backing-up (not necessarily the entire size of your internal HD).
But this varies greatly, depending on how you use your Mac. If you frequently add/update lots of large files, then even 3 times may not be enough. If you're a light user, 1.5 times might do. Unfortunately, it's rather hard to predict, so if in doubt, get a bigger one!
Also, there are some OSX features and 3rd-party applications that take up large amounts of backup space, for various reasons. See question #9 for details.
This is a trade-off between space and how long TM can keep its backups, since TM will, by design, eventually use all the space available. But it won't just quit backing-up when it runs out: it starts deleting the oldest backups so it can keep making new ones. Thus, the more space it has, the longer it can keep your backups."
Regards
Stefan

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Backup Drive for Time Machine FILLS UP FAST!

*Be forewarned!*
I have a new iMac 2.8 GHz with an internal 750GB drive (about 500GB free). I bought a 500GB external drive (Western Digital Book My Book™), and after just 4 days of running with Time Machine turned on, I get this error message, "Time Machine backup failed. Time Machine needs 175GB to backup, and only 150GB available." Huh?
I just spoke to someone at the Apple Store's Genius bar, and they recommend a backup drive that is twice the size of your internal drive. (which means a 1.5 TB drive: not cheap...LaCie costs $539)
Also, come to find out some programs simply "don't play nice" with Time Machine. A good example is MS-Entourage, which has a single database file (in the Main Identity folder) which holds all the info for your email, address book and calendar. Mine is 350 MB in size, and it is being backed up IN FULL every hour because, well...I use my email. And every time any changes are made to that single file, it is considered modified, which means it is backed up every hour on the hour, which can quickly add up.
The same is true for the Windows XP or Vista VM files created by Parallels or VMware Fusion. Each are single, 2+ GB files, and each time any change is made to this 'huge' file, it gets backed up repeatedly by Leopard's Time Machine.
_So the larger the backup drive for Time Machine the better_! I'm considering giving up on Entourage (kiss Microsoft goodbye!) and switching to Apple's excellent mail, address book and calendar programs!
Tim Liszt
LisZt Design

Tim,
I just switched from Entourage to Mail (for many reasons). Thus far, I love Mail. You may want to get the Widescreen plugin for it if you like the three-pane configuration of Entourage.
You should also be careful with Address Book if you have syncing set up in Entourage. In other words, probably should turn it off, along with any daemons you may have running. I lost data twice (once before my very eyes!) until figuring this out. Used Time Machine to restore a previous address book with all my contacts.
Thanks for the other information on this thread. Since I should be upgrading my old external drive anyway, it will help in purchasing a new machine for use with TM.
Message was edited by: SPD

What size ext. hd for time machine

I'll be upgrading to Leopard in the next two weeks, and I was wondering what size external hd i should be looking at. I'm looking at the Western Digital My Book Premium Edition, which I found the 500gb version for $150 and the 750Gb version for $230. Is it worth the extra $80 for 250GB more hd space? How much space do I need to back up my 250GB drive (with 140GB used)??? Does Time Machine compress files at all??? Thanks for your response.

I have a similar situation. I have a 500gb iMac with 350gb used. I have a 500gb ext. hd with 465gb available. Time Machine (horrible so far in my opinion) claims I don't have enough room to run it. The math I learned still proves that 465 is greater than 350.
Not only that but installing Leopard was excruciating. If you have yet to install it, make sure you run the installer as archive then install and not upgrade. Upgrade will give you blue screen of death. Why did Apple, my favorite computer company, release an os with features that create so many windows like issues. So far I am nothing even close to excited, nor even satisfied with this $140 upgrade.

Invalid Checksum when trying to use Seagate Backup Drive for Time Machine

Hi,
I'm trying to use a Seagate Backup Plus Drive with my Mac. It was originally used with a Windows machine. It does have the Seagate Dashboard Installer.dmg file. When I try to install it, it gives me an "invalid checksum" error.
I've also opened it in Disk Utility and attempted to reformat it into the Mac OS Extended (journaled) format, but it says it could not unmount the disk. I cannot see that it has any opened files that would be causing this problem. Any suggestions?
Thanks!

Tim,
I just switched from Entourage to Mail (for many reasons). Thus far, I love Mail. You may want to get the Widescreen plugin for it if you like the three-pane configuration of Entourage.
You should also be careful with Address Book if you have syncing set up in Entourage. In other words, probably should turn it off, along with any daemons you may have running. I lost data twice (once before my very eyes!) until figuring this out. Used Time Machine to restore a previous address book with all my contacts.
Thanks for the other information on this thread. Since I should be upgrading my old external drive anyway, it will help in purchasing a new machine for use with TM.
Message was edited by: SPD

First Imac in the post. What size hard disk for Time Machine

I have a 500GB hard disk in my new imac (Which I dont have yet)
What size drive should I get to backup my system.

Peggy's answer is essentially correct. OTOH, if after moving into your new computer you are using only 40GB of that huge drive, it would silly to get a 1GB drive, at least until you've found a way to fill up more of the drive....and you will eventually. So to amend Peggy's answer, look at how much drive space you are currently using. If you own a digital camera figure you could easily fill 1GB a year per child. Music and/or Video? Estimate how much you've added in the last year and use that as a rough bench mark. Add another 5GB and add all that together to see how much of your drive you'll have filled by this time next year. Use that to gauge how big your external TM drive should be, based on the 2 to 3 times bigger figure.

My 320GB external drive for Time Machine now only has enough capacity to keep a backup of one day. All my other backups are gone. What can I do to fix this situation?

I've been using a 320GB external drive for time machine for the last several years. The backups always worked fine and when necessary I was able to look at & restore older data from the time capsule. Recently, I keep getting the message that a backup cannot be completed and an older backup will be deleted. Usually this wasn't an issue because I still had several months of information on disk. Now a one-time backup takes up 315GB and therefore I only have a backup of the previous day. I don't understand this because I thought that the backup only saves information that has changed and doesn't copy everything everytime. What do I need to do to get my backups to a reasonable size so that I can keep at least 1 month data stored on it.? Please don't tell me I need a larger drive ... that would be too easy.

Get a larger drive for your TM backups.
The recommended size is 3 times what you are backup. So if 315 GB is a backup then you need a 1 TB drive.
Allan

Is it possible to use more than one external hard drive for Time Machine backups?

I want to use two hard drives for Time Machine backups.
Bigger one keep at home and be sure it is safe.
Second one (very small pocket size) keep with me for travels.
I want to backup to both drives to be sure I can restore everywhere and to be sure if something bad happened with my small travel disk I can restore from home backup.
Is there any problem with listed schema? Is it normal for Time Machine to handle backups for different drivers and keep everything consistent and smooth?

I really need some help! I have been using an Iomega NAS 1TB HD for the past year. And I received an error message. I believe I have ran out of memory on this drive.
Then recently in the last couple of months I got a ReadyNAS Duo 2TB with 2TB RAID. Should I switch my back ups to this one and delete the other back up file or keep the old back up image file on the Iomega?
Can I transfer the old image back up to this new ReadyNAS? How do I do this?
I appreciate any help.

HT201250 How can I revert to my internal drive for time machine backups after using an external drive?

Hi. I've been using an external drive for time machine back ups and decided to revert to my internal drive, but it isn't available in the time machine options. The only available option is to set up a time capsule, which I don't own.
Is it because not enough space is available on my internal drive (approx 50GB)?
Thanks!

50 Gb free on your internal drive is relly very low and of course not enought for a any kind of backup.
How big is your internal HD ? If you have left only 50 GB free it is probably 90% full. Let's imagine you have a 500 Gb. This means 450 Gb data and 50 Gb free. How can you backup 450 into 50 ?
Second point. The backup on your internal HD is a nonsense evenif it is big enough. If it stops working you will have no bakup.
Do you have an iMac or a portable ?
The portable automatic uses the internal HD if the external is not connected, but this is intended for a short time.
This could give you some more links to read about https://discussions.apple.com/message/20726927#20726927

Is it possible to use an external hard drive for time machine backup and also as a regular hard drive?

Is it possible to use an external hard drive for time machine backup and also as a regular hard drive?

I am using an external drive in the exact way that you described. You just keep it plugged in to the computer when you want to access the movies and files. In order to put files on it, just go to finder open up the drive under devices and drag and drop files onto the drive. It is just like using a usb drive with a terabyte of space.

Brand new iMac 23.GHz Intel Core i5. Mounts external drive for time machine, then dismounts after backup is complete.

brand new iMac 23.GHz Intel Core i5. Mounts external drive for time machine, then dismounts after backup is complete.

The warranty entitles you to complimentary phone support for the first 90 days of ownership.
If you bought the product in the U.S. directly from Apple (not from a reseller), you have 14 days from the date of delivery in which to exchange or return it for a refund. In other countries, the return policy may be different. If you bought from a reseller, its return policy applies.

HT201250 new external hard drive for Time Machine backup suggestions?

Ok, I have 3 external hard drives; unfortunately I've used them on my PC and they are read only on my iMac. So, I need to buy a new external hard drive for Time Machine backup. I'm a little confused; can I buy any EHD and them format it so Mac can use it or are there special EHD's I need to purchase?
Anyone have a particular EHD that is working well for you? Thanks, Blue

Bluehowler wrote:
Ok, I have 3 external hard drives; unfortunately I've used them on my PC and they are read only on my iMac. So, I need to buy a new external hard drive for Time Machine backup. I'm a little confused; can I buy any EHD and them format it so Mac can use it or are there special EHD's I need to purchase?
Anyone have a particular EHD that is working well for you? Thanks, Blue
Unless you need all three external drives for your PC, you can reformat in one of them in Mac OS Extended (Journaled) for use with Time Machine. However, since Time Machine backs up hourly, you'd need the external drive to be running constantly. That means ventilation of the drive becomes an issue since some, such as Seagate, can get very hot in their sealed enclosures. Some drive manufacturers try to get around this by spinning down the drive when not in use, but I've read complaints that that doesn't play well with a Mac. So whether you reuse one of your current externals or get a new one, it's a good idea to keep the drive's ventilation in mind.

If I choose a hard drive ask my backup disk for time machine, will it clear out the data that was previously stored in my hard drive?

If I choose a hard drive ask my backup disk for time machine, will it clear out the data that was previously stored in my hard drive?

Hello edjhsu,
Unless the drive is in a format that isn't compatible with Time Machine, the files will not be overrwitten. However it is typically a better idea to keep your files and your backup separate, especially since files on the Time Machine drive will not be backed up by Time Machine.
Mac Basics: Time Machine backs up your Mac
http://support.apple.com/kb/HT1427
Cheers,
Allen

Unable to select two drives for time machine backup?

I had a notification from Time Machine saying "This backup is too large for the disk..." and that I needed to omit items or select another drive. I've read online that it's possible to select multiple drives for Time Machine backups (so it switches between the available drives). When I go into Time Machine preferences and click "Select Disk" the drive I want to use in addition to my current Time Machine is there, but when I choose the additional drive I do not get the option to replace or "Use Both" (like pictured). Instead the additional drive is selected as the sole Time Machine and the current Time Machine drive is replaced.
In short, Time Machine is not giving me the option to "Use Both" - why would this be and how do I remedy this?
Thanks.

The reason is that that feature is Only offered in "Mountain Lion" OS X 10.8; and you are using "Lion" 10.7.
Hope this helps

New larger disk drive for Time Machine ..having trouble using it.

I must be missing something simple here. My Time Machine drive was getting pretty full so I went out and bought a larger drive. I assumed I could copy everything on the old drive to the new one ..then start up Time Machine and point it to the new drive and be in business. Not so. When I tried to copy the contents from one disk to the other the process locked up after about an hour. All activity stopped and I had no files on the new drive. To troubleshoot I simply copied a small folder from the smaller Time Machine drive to the new one..and it copied fine. However I noticed the date on the copied file was current so I assume my process is not a good one anyway as all the dates will be lost. Guess that will screw up Time Machine (after all what is time if its all the same ?). So ..how do I use a new larger drive for Time Machine..without loosing all the old stuff that is already saved. If I just select change disk from the Time Machine panel I assume I will only get backups from now ...and nothing older (from the old disk). I do not want to keep the older disk connected. So what am I missing here ??

Pondini wrote:
And I forgot to add: Disk Utility will do it.
I missed your post this morning.
I looked around and found the keys to get Disk Utility to do it. No $$ needed.
Thanks for the info.
For the rest of the viewers:
*How to change the Time Machine backup disk and migrate the current data to the new disk*:
This procedure performs block transfers, not file-by-file transfers. It avoids all the extended attribute, ACL and hierarchical problems. It just works - it's a Mac!
System Preferences:
..1 - Time Machine:
....1.1 - Turn OFF
..2 - Spotlight:
....2.1 - Privacy:
......2.1.1 add current TimeMachine volume to prevention list
......2.1.2 add new TimeMachine volume to prevention list
Disk Utility:
..1 - Select the target drive in the left pane
..2 - Select Partition tab
....2.1 - Volume Scheme: *1 Partition*
....2.2 - Options: *GUID Partition Table*
....2.3 - Select Apply -> Partition
..3 - Select Restore tab
....3.1 - Drag source Volume into Source window
....3.2 - drag destination Volume into Destination window
....3.3 - Check box: *Erase Destination* ( +this is the critical step+ )
....3.4 - Click Restore button (Wait for transfer to complete, minutes to hours depending on size & disk connections)
The source and destination volumes will now have the same name. Change the volume name(s) as desired.
System Preferences:
..1 - Spotlight:
....1.1 - Privacy: add new TimeMachine volume to prevention list
..1 - Time Machine:
....1.1 - Turn ON
Done!

External drive for Time Machine

I want to use a 3 TB external drive for Time Machine to backup multiple 500GB hard drives in my Macpro. I have lots of large video files from HD cameras.
1. Will Time Machine backup all of the hard drives in the Macpro?
2. What is a good external hard drive to handles these types of files?
Thanks.

kat.hayes wrote:
I want to use a 3 TB external drive for Time Machine to backup multiple 500GB hard drives in my Macpro. I have lots of large video files from HD cameras.
1. Will Time Machine backup all of the hard drives in the Macpro?
As long as they're formatted HFS+, yes. Be sure there's enough room, though -- Time Machine needs considerably more room than the data it's backing-up. See #1 in Time Machine - Frequently Asked Questions.

What size backup drive for time machine on 500gb MBP?

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