Thanks for the suggestion. I resolved it on my Mountain Lion 10.8.2 system,
without any command line hacks (since that can complicates support if
one needs resort to it later).
I realized my first priority was backups, with Spotlight indexing behind that.
After reading various forums, it seemed likely that Spotlight was thwarting
Time Machine, not the other way around. So here's what I did:
1. Went to Energy Saver preference panel and disabled automatic power off
of system (and disk drives), until such time as the issue was resolved.
2. Stopped Time Machine (since it hadn't accomplished much more
than 4Gb in 24 hours),
3. Removed Time Machine backup disk as Time Machine's backup target drive,
effectively disabling backups (in the time machine dialog, I didn't physically
remove any drives).
4. Dragged system disk into the privacy column, in Spotlight Preferences,
under System Preferences, which terminated Spotlight's indexing efforts
5. Booted system in failsafe mode, ran disk utility, fixed permissions
and repaired system disk, though it reported no errors.
6. Rebooted Mountain Lion 10.8.2, normal mode
7. Set Time Machine backup disk again.
8. Time Machine steadily backed up and completed 200Gb in 2 hours,
never pausing for any noticeable amount of time.
9. When Time Machine completed, I went back to Spotlight Preference pane,
and removed the system disk from the privacy list.
10. Spotlight started indexing, reporting a 20 minute completion estimate, within
a few minutes of starting. (When it was in the stuck mode, previously, it kept
promising an estimate, but never arrived at one).
11.Spotlight completed on time and both Spotlight and Time Machine
have been working flawlessly ever since.
I suspect what got me into trouble was that I used Migration Assistant
to bring over another system. But there was a conflict with new and old
user names, and so I wound up renaming accounts and having to chown -R
my home directory (I'm a unixy guy). While I was doing that, spotlight
was probably indexing and got confused by the way things were changing
around beneath it.
Message was edited by: Cyberspace Travel
Yes, I'd already established an account with the same name as I had on the old system, on the new system, before attempting the migration, so it reported a conflict and forced me to rename the incoming account that had the data I wanted to keep, away from the original user name.
So, after Migration Assistent completed, I renamed the new (empty) account out of the way, and renamed the incoming acount to its original name, and then determined the user IDs/names of the new and old users and did a chown -R of the renamed directory to match the account I'd just moved the data over to.
Not too happy about the way Migration Assistant and the Users & Groups preferance panel handled that, as it wasn't obvious how to proceed there, but my plan worked, other than thwarting Spotlight. So all is good now.
I've been having speed issues lately with my Time Machine backups so ended up reading the entire thread. I think I did the supplemental update when it was issued, I am however in the same situation.
My setup backs up on a network drive (USB HD connected to another iMac on the network running 10.8.2) and it's been a few days now it needs an hour for an 80MB worth of backup data. Reinstalled 10.7.5, applied supplemental update just to be sure, but things are not pregressing as expected.
Will try deleting the entire Spotlight index and check again.
I have also tried changing the Time machine destination using "tmutil setdestination" command to the mounted sparseimage volume and not the network drive. That way, the backup finished almost instantly, but upon changing the target back to normal (selecting the network disk through TM preferences), I am still getting very long backup times.
I have tried all of the troubleshooting techniques in Pondini's tutorial, however I have been unable to fix the issue. The only way to make TM work as fast as it used to is to set the target to the mounted volume using tmutil setdestination. That way, both backing up and searching though the TM database works blazing fast. However, as soon as I switch back to normal (that is, setting the network drive as the destination) the whole thing becomes sluggish again.
My next bet is upgrading to Mountain Lion, but I am readings about some similar issues over there, too...
Time Machine automatically skips a number of things, including the Spotlight index, system work files, most caches and logs, trash, etc. See the tan box in Time Machine - Frequently Asked Question #11 for the gory details.
Since many or most of those change frequently, they'd have to be backed-up in full on each backup, taking time and space on the backup drive, without accomplishing much at all.