[CentOS] fsck.ext4 huge memory usage

I have a 5.4TB file system, ext4, that currently is reporting problems, 
however, every time I run fsck.ext4 on the file system, it grows to more 
than 17GB.

Can anyone tell me WTF is going on here?  Why is it using so much disk 
space?

-- 
James A. Peltier
Systems Analyst (FASNet), VIVARIUM Technical Director
HPC Coordinator
Simon Fraser University - Burnaby Campus
Phone   : 778-782-6573
Fax     : 778-782-3045
E-Mail  : jpeltier at sfu.ca
Website : http://www.fas.sfu.ca | http://vivarium.cs.sfu.ca
           http://blogs.sfu.ca/people/jpeltier
MSN     : subatomic_spam at hotmail.com

TEAMWORK
  There's power in numbers.  Learn to work together.