Time Machine.. miracle app?
I saw the stream and there is something I don't understand about Time Machine...
he says that "even if I lose the hard drive, I can still recover all my data"
I'm paraphrasing (the WWDC feed is down now, cant skip to it...)
How the hell can you possibly recover all your data from a hard drive that dies??? Or does he mean that "obviously" everyone has 2nd hard drive? I really dont get it.. the Apple page also doesnt clarify much
And. good god. How much space is it going to take!?!? I move about 5-10GB of data per DAY (downloads, content creation, etc), I'd run out of hard drive space in weeks despite having 2 x 400GB dirves.
Any further info from anyone?
he says that "even if I lose the hard drive, I can still recover all my data"
I'm paraphrasing (the WWDC feed is down now, cant skip to it...)
How the hell can you possibly recover all your data from a hard drive that dies??? Or does he mean that "obviously" everyone has 2nd hard drive? I really dont get it.. the Apple page also doesnt clarify much
And. good god. How much space is it going to take!?!? I move about 5-10GB of data per DAY (downloads, content creation, etc), I'd run out of hard drive space in weeks despite having 2 x 400GB dirves.
Any further info from anyone?
Comments
Oh sure I guess you could partition a drive into two logical partitions but if the drive (mechanically) bites the big one then both partitions will be lost. If however the drive has some kind of major corruption where a format will get you going again then I'd guess you could get away with a single drive...
To be safe fork over the money for an extra drive. I can find 350GB SATA drives for under $100 all the time now (with no silly mail in rebates)
Dave
ie, you still need a backup drive. (or a backup server, in MacOS X Server 10.5, but most folks won't have that...)
Still.. are the backups highly compressed or what?
I stopped using .Mac Backup because I was auto backing up every day to my 2nd HD and by the end of a month I had no space left..
So, yes, now I just manually backup my folders every few weeks...
Too many questions, no answers.
rsync only copies files that have changed. Hard links are used to make it *look* like every file was copied, but they take up almost no space. No compression needed, and it only copies the files that have changed.
If I change a file daily, and have daily backups, then I can flip back through today (on main HD), yesterday, the day before, the day before that, etc, and see each changed version. If I change a file weekly, I can *still* flip through daily backups, and it won't change - but it also doesn't take up umpteen copies of the same data - there's one copy of it, and umpteen hard links pointing to it. Hard links are like aliases, but really *ARE* files in their own right. (Voodoo. Just keep telling yourself it's happy shiny voodoo.)
You just have to do it carefully - Time Machine really does feel like a simplified GUI version of that though.
"Show me the latest change to /System... uh... I didn't update that day... er... problem?"
No idea on compression - I use a rotating fileset with rsync and hard links, and backup an 80GB drive to... an 80GB drive. Works well for up to about 10 sets. Most likely you can set the rolloff point, or it'll just silently remove the oldest (or maybe give it greater granularity?) when space gets tight.
rsync is mind-bogglingly powerful isn't it? We use it and hardlinks to back up our linux servers.
Only the modified blocks of files need to be written over the network. Given our usage patterns, a week's worth of daily snapshots need only 1.5 times the space of the original data. The data is uncompressed and access to it is just as quick as for "real" files. Once we realized this, we decided to go for hourly backups as well. With 24 hourly snapshots from the previous 24 hours, we still use less than 2x the storage as the live data.
I can't wait to find out what apple's implementation is based on (if anything). I'm guessing that time machine is built atop a couple mature/legacy command line utilities...