Time Machine oddities

[Charles Dyer]

Not only is Time Machine extremely slow in doing the initial backup  
(over 36 hours to back up 343 GB, 24 hours to back up the first 168  
GB, 12+ to get the rest) but it has very strange ideas about which  
volumes should be backed up.

I have an external DVD drive which is attached to my system but not  
usually turned on. It's an old DVD-ROM liberated from a graphite G4  
after I installed a DVD burner instead; I placed the old DVD into an  
external FireWire drive, and have used it ever since. It was, I  
repeat, liberated from _Apple_ equipment, and works properly and has  
for years.

This morning I had the DVD turned on when TM started its hourly  
backup... and TM reported that it couldn't back up because one of the  
volumes I was backing up was case-sensitive, and the destination  
volume was not, and TM would not back up case-sensitive volumes to non- 
case-sensitive ones. The only difference that I could see about that  
particular backup and the one TM had performed an hour earlier was  
that an hour earlier I'd not had the external DVD in use. I checked,  
but TM didn't seem to be backing up anything from the disc, but I  
figured that it _must_ be. I finished what I was doing, and when done  
ejected the disc. TM ran again... and again said that it couldn't back  
up because there was a case-sensitive volume present.

I checked _everything_. No new volumes on the volume list. Nothing in  
the DVD drive, or in the internal SuperDrive. No new drives, no new  
network volumes, nothing. All volumes formatted HFS+, non-case- 
sensitive. I turned _off_ the external DVD. The next time TM ran, it  
worked fine. I turned the external DVD back on. The next time, TM  
failed again, with the same error message.

Time Machine was detecting the _empty_ DVD drive. There was nothing in  
it, but TM thought that there was something there which was formatted  
HFS+ case-sensitive... but whatever it was didn't show up on any list  
of volumes to be backed up or excluded or anything, which is logical  
as there wasn't anything there.