Rebuiling volume for external drive - filling up system drive in /private folder

[bluemix]

I have an external storage drive (USB - 1.5 TB) that will no longer show up as an icon on the desktop. I tried rebuilding the file system and all hell broke loose. The rebuild never finishes but the system drive has been completely filled. /private/vm fills up as does /private/log.

I have searched online and have seen these problems but not in this particular case (rebuilding external drive) - am I doing something utterly stupid? Am I supposed to know that I need a certain amount of space on the system drive in order to rebuild a huge external drive? If not, what is going on?

I used the terminal based on my online reading to find the offending files/folders but am not well versed when it comes to terminal commands.

Any help would be greatly appreciated!

Thanks.

EDIT - I cleaned out the offending files etc. and have the OS up and running properly but trying the rebuild again is causing the same issue...

2nd EDIT - don't know if this is helpful but... syslogd is running like a mad dog during the rebuild process

 

[bluemix]

Update

5 Hours and 20 min into the new attempt to rebuild the external drive's file directory. I cleared out 50 GB from the system drive and the /private folder is already back to 49GB - full of swapfiles all 1.07 GB each in the /private/vm folder.

When space runs out again what happens to the rebuild?

So this is obviously a case of requiring far more space on the system drive than is available, in order to successfully rebuild the external volume. Is it just me or is it too much to ask of the software (before it begins the entire rebuild process) to realize that there isn't enough space on the system drive to do this? Would this not be a simple analysis task before 5hrs and 50GB disappear?

Any help or advice would be greatly appreciated.

Thanks!