View Full Version : Automated Backup Scheme with History

07-03-2008, 03:57 PM
I have been using SD! for a while and love it. However, I run it manually, and therefore there is some risk because my backups are at the mercy of whenever I remember to do it. In the event of an emergency, my backup may be several days old. Also, I am not really protected in the event I unwittingly deleted a file *before* my last backup (i.e. I need some kind of historical archive to pull from). Basically, I really need to step up my game with backups, because my business depends on my computer. So, here's what I want to do:

1. Create a automated backup system that will run at night, automatically
2. Create historical backups of my system that are updated automatically
3. Be protected against data loss by theft, both when I'm in the office AND traveling

My first thought was to use Time Machine (I run Leopard on a MBPro). After some research I dumped this idea because most of my "Home" files (the files that I use every day) reside in a 30GB encrypted disk image which I mount when I log in (data security measure). Time Machine wouldn't be able to handle that properly. I don't want the files stored on an external drive in an un-encrypted state (in case it's stolen), which means TM would just be keeping historical copies of my 30GB disk image, which isn't an advantage over SD! I hear TM is buggy in other ways too...

So my next idea involves 2 external drives. One is a 2.5" drive that will contain nightly backups (I travel with this, in the event my laptop dies when I'm on the road), and the other is a 1TB external drive (amazingly cheap, btw) partitioned into 4 parts, each the size of my MBPro's hard drive. Each partition will contain a complete "All Files" backup of my drive that is x number of days old. So it will look like this:

250G Drive: gets complete backup nightly
1TB Drive Partition 1: complete backup from 1 week ago
1TB Drive Partition 2: complete backup from 1 month ago
1TB Drive Partition 3: complete backup from 3 months ago
1TB Drive Partition 4: complete backup from 6 months ago

The key here is that I need this stuff to happen automatically. If I have to remember to do it, there's just no way this is going to work. I know there's a SD! limitation that the computer has to be on, and the user running the process needs to be logged in, which does throw a wrench into things. For security, I do not auto-log-in any user (for theft protection). But I did some searching in this forum and it appears that if I schedule my mac to start up at a certain time (say, 3am), as long as SD! scheduled as root it will be able to run with no login necessary. Can somebody confirm that?

Provided I can do that, I should be able to schedule the nightly backup, and also schedule the "1 week" partition to update weekly, the "1 month" partition to update monthly, and so forth. And provided my 30GB encrypted disk image isn't mounted (which it wouldn't be, if I scheduled the computer to start up before SD! runs), then the backed-up data would be secure in the event one of the external drives was stolen.

Only problems I see with this are A) if my computer and both external backup drives are stolen at the same time (like, if somebody broke in) - I'm basically screwed. The only mild peace of mind I'd have is that all my sensitive files are in an encrypted disk image. But obviously I don't have my data so I can't do business. B) my backup drives are not RAID so if for example my 1TB drive failed, I'd lose all my backup history. Not a super huge deal since my data would still live in 2 other places (on the other backup drive and on the computer itself). C) My "historical" backups wouldn't be truly historical since I'd be updating them directly from my MBPro drive. For example, my "6 month" history would never truly be 6 months old because I'd update it every 5 months and 31 days with current data. So, on 6 months and 1 day, the data on my "6 month" drive is only 1 day old. Still trying to wrap my head around this. If you have any ideas, let me know.

Can anybody see any other issues with this? Anyone have any better ideas on how to accomplish my goals?

07-03-2008, 07:17 PM
Although the "root" trick should work, I don't know if it'll work under Leopard. You can certainly try, though. Alternatively, you can use a non-privileged account. Leave that logged in and in front when you shut down, and it'll back up from there, with no risk to your stuff (and certainly less risk than a root install).

And, sure, you're screwed if things are stolen and everything's there... but if that's a concern, perhaps it's time to do an online backup too.

And, yes -- you aren't guaranteed that one backup is always 6 months back -- it's a MAXIMUM of six months back, unless you rotate two six month backups.

07-03-2008, 07:50 PM
Thanks for the reply! I just want to clarify what you mean about the non-privileged user. I understand it would be safer to run scheduled tasks as a non-root user, but I am not clear about what you mean about leaving the user logged in and in front when I shut down. Unless I'm missing something, when it starts up for the scheduled backup, it's not going to know what user was logged in. Do you mean that I set it up to auto-login to a non-privileged account?


07-03-2008, 08:22 PM
If you're literally shutting down, yes (although you're not likely going to get a consistent enough startup to get in there and ready for a backup after the wake event). But I'm thinking more of you logging out and into the non-priv'ed account, then sleeping.

07-04-2008, 05:22 AM

consider maybe in addition to Clones Retrospect Desktop. When you tell it to run (automated) backups off your mounted encrypted image, it should be able to put only the changed part into a backup-file either on another HD or onto DVDs. Retrospect has pretty tough encryption as an option. The only problem would be that the catalog to read that growing file would grow as well and needs to be backed up for convenience (one can restore a catalog-file off the backup-file but that takes a huge amount of time).

Retrospect runs in Rosetta, so there is a slight but not too great speed-penalty if you run it during the day instead of during the night and donot want o keep you encrypted image open. If you run it as part of your shut-down-procedure that might work.


PS: have a look at the latest TakeControl on Backups and the free online-primer on Retrospect at http://www.takecontrolbooks.com/resources/0014/retrospect.html

08-31-2008, 02:11 AM
I do this: I have TWO external backup drives (in addition to Time Machine and a network drive), and keep one of them in a bank safe deposit box and one at home. Then once every month I clone my hard drive using SD and then swap it with the one at the bank. If my backup drive at home gets stolen, then at worst I've lost only a month of data (as opposed to ALL of it). It's not automatic, but is not that cumbersome, either. Even if you are lazy and only do this twice a year, well you can potentially only lose half a year of data at worst. Didn't you say your business depends on this data?

Off-site backup is crucial - besides theft, there is also risk of fire, accidental damage, lightning, etc.

You might also want to check out something like Jungle Disk to back up to Amazon S3. The data is encrypted and is stored on Amazon's geographically dispersed servers.