[ale] why would it take longer to delete a file than to create it?

[John G. Heim]

I have this very slow database server. Today I noticed something strange 
about it. I can create a large file via dd faster than I can delete it. 
Look at the screen cap below... It took just 12 seconds to create the file 
with a million 1K records but it took 36 seconds to delete it. Why would 
that be? I'm running debian lenny with a 2.6.30 kernel. There are 2 500 Gb 
disks in the machine configured as RAID-1.  The file system on the disk is 
ext3.

# date; dd if=/dev/zero  of=zero.txt bs=1024 count=1000000; date; rm 
zero.txt; date
Tue May  4 16:59:21 CDT 2010
1000000+0 records in
1000000+0 records out
1024000000 bytes (1.0 GB) copied, 11.7291 s, 87.3 MB/s
Tue May  4 16:59:33 CDT 2010
Tue May  4 17:00:09 CDT 2010