need help with approx-gc

[Paul E Condon <pecondon@mesanetworks.net>]

I run approx on one of my local jessie machines. The approx installation
is strictly by using the approx deb, which includes a weekly run of
approx-gc , which should just clean out the local repository of debs that
are no longer useful. But approx-gc has started reporting I/O errors.

I suppose I could just delete the repository and let my future use of
aptitude refil it, but I'd like to start learning  how to deal with
this with a little more finesse. I suppose that I might be able
to run approx-gc in some sort of debug mode, and discover what file
or directory is giving it trouble. So far I have run manually which gives:
root@cmn:~# approx-gc -s -v
[ security/dists/jessie/updates/non-free/source/Sources.bz2 ]
[ security/dists/jessie/updates/non-free/binary-i386/Packages.bz2 ]
[ security/dists/jessie/updates/contrib/source/Sources.bz2 ]
[ security/dists/jessie/updates/contrib/binary-i386/Packages.bz2 ]
[ security/dists/jessie/updates/main/source/Sources.bz2 ]
[ security/dists/jessie/updates/main/binary-i386/Packages.bz2 ]
Input/output error
root@cmn:~#

I am running with a single large (160GB) root partition that is 7% in use. 
Is there a standard sysadmin procedure for diagnosing this?

Best Regards,
-- 
Paul E Condon           
pecondon@mesanetworks.net