I'm asking myself and repeat a question I read on the forums, what happens if a nodes blkindex.dat grows larger than what we allow for blk000x.dat or (if that size-limit doesn't matter here) larger that the max FAT32 filesize (4 G(i)B - 1 Byte AFAIK)?
Seems like "blkindex.dat" is also hard-coded in some places. Comments / ideas?
See http://doc.gnu-darwin.org/am_misc/dbsizes.html
Short answer: blkindex.dat will eventually break if it gets bigger than the underlying filesystem supports.
I would vote for "Don't run a full bitcoin node on a FAT32 filesystem", along with a tiny bit of code to warn the user if they try to do that (is there a POSIX call to get the maximum supported file size for a given filesystem?)
Pieter's "ultraprune" work might make blkindex.dat go away before it reaches 4GB, though.
BDB currently managed blkindex.dat, and I suppose it is as good as handling large files as the underlying OS and filesystem are. I wouldn't worry about this, especially since we're working on several things that will change this radically anyway.
Seems obsolete with the change over to LevelDB, so closing it.