Time Machine deletes all but latest two backups

Question

Hello,
Today I was backing up my macbook, with about 38 GB of space left on my harddrive, and Time Machine deletes everything but the latest two backups (from Feb 2012 to May 2012).... I had things on there from 2009. TM preferences now says I have 27 GB of free space, after the latest backup. I didn't have anything big enough on my computer to be backed up that justified deleting years of data, over 200 GB, in order to compensate for the new data that had to be backed up. Is there any way to recover the files that were erased off of my external hard-drive that were deleted during Time Machine's semi-routine back up?
Thank you

Answer 1

Sebastian Kuhn wrote:
Is there no way to set up Time Machine such that it will ASK before destroying a (potentially valuable) "old" backup
That's how it worked at first, on Leopard.  But many users either didn't understand it, or never got around to doing anything, so had no backups at all when disaster struck.  It was fairly common, so Apple changed it with Snow Leopard.
Why does Apple assume that it is always the OLDEST backup (which will be hardest to retrieve) that people would be willing to loose?
That's usually correct.  Time Machine is not a traditional archive-type app;  if you need archives, make archives.
If you frequently need things from your backups, you may have a deeper problem.  But most likely, you just need a larger backup drive. 
That all applies to the vast majority of users -- they have a single internal HD with less than 1 TB of data, so a 2 TB backup drive is ok, 3 TB large enough for most everybody.
If that's not enough for your setup, you probably need a different strategy anyway.  You may have some data that changes frequently and should be backed-up hourly by Time Machine, plus something like a large media drive that's best backed-up only once a day or so by a different app, such as one of the "cloning" products. 
there should be the option to exclude different items when backing up to different disks. Is there?
No.  Apparently Apple wants to keep it as simple as possible, with  few options that may confuse some folks, so instead of making a decision, they do nothing  (that's not just Time Machine, either).  Remember, most of the folks using Time Machine have never used any backup app at all. 
Apple's resisted all suggestions (and there have been many) for things like the ability to limit the size or age of backups, reduce the 10-day warning when no backup has been done, etc.  Like it or not, that's Apple's approach to pretty much everything -- streamlined, simple, easy to use.  Very successful for the majority.
Is there any workaround other than the cumbersome procedure of turning Time Machine off, and under "options" re-select the correct set of folders to exclude every time I move from one disk to another? Not exactly what I would call a user-friendly interface...
Best of course, is get a larger disk.  Is your data worth the price of a 2 TB disk? 
There are some elaborate workarounds involving automatically swapping destinations and exclusions, but they're very "iffy" as they do things that TM (and OSX) don't anticipate so don't react well to.
Effective with Lion, however, there's a new tmutil command that in theory would allow you to write an AppleScript to set a destination, add or remove exclusions and run a backup.  Many things could go wrong, of course, but I know of no way to detect which destination is available. 
Much safer, easier, and more reliable to get a larger drive (or better strategy).