18-Nov 12:45 maple-sd JobId 46: Sending spooled attrs to the Director. Despooling 153,470,245 bytes ...
18-Nov 21:41 maple-dir JobId 46: Bacula maple-dir 5.2.6 (21Feb12):   Build OS:  x86_64-pc-linux-gnu ubuntu 13.04

So spooling/despooling took just about 9 hours.

Even for MySQL on a not too fast machine this is ridiculus slow. We  
despool around 1.2GB attributes within around 2 minutes to our  
Postgres server. Something is still wrong with your setup. Have you  
checked with tools like iotop,top,vmstat what the server is actually  
doing during the 9 hours.

Regards

Andreas

iostat during the attrs despooling shows:
                                           
  334 be/3 root        0.00 B/s    0.00 B/s  0.00 % 99.99 % [jbd2/sda1-8]
24997 be/4 mysql       0.00 B/s   64.98 K/s  0.00 %  0.12 % mysqld

Doing some research this appears to be a problem between MySQL and ext4
with file system journaling (jbd2/sda1-8).

Thanks, everyone, for helping me get this far. 

My next step will be to create an ext3 partition and move all my MySQL
Dbs there.


Sorry for the delay in presenting results, but when I first tried to create an EXT3 partition I discovered I was also having a huge number of read retries on that particular hard drive.  To rule out the possibility that this was the problem I first replaced the hard drive and re-ran a backup with the MySQL database on an EXT4 partition on the new hard drive.  I had the same issue.

I then created an EXT3 partition and moved my MySQL database there.  The new results are:

02-Dec 02:46 maple-sd JobId 107: Sending spooled attrs to the Director. Despooling 153,749,840 bytes ...
02-Dec 03:52 maple-dir JobId 107: Bacula maple-dir 5.2.6 (21Feb12):