missing objects -- prevention

Hi all,

I find a lot of info on how to recover from and/or repair a repo that
has missing (or corrupted) objects.

What I need is info on common reasons (other than disk errors -- we've
checked for those) for such errors to occur, any preventive measures
we can take, and so on.  For example, can *any* type of network error
or race condition cause this?  (Say, can one push writes an object,
then fails an update check, and a later push succeeds and races
against a gc that removes the unreachable object?)  Or... the repo is
pretty large -- about 6-7 GB, so could size cause a race that would
not show up on a smaller repo?

Anything else I can watch out for or caution the team about?

The symptom is usually a disk space crunch caused by tmp_pack_* files
left around by auto-gc.  Presumably the missing objects failed the gc
and so it left the files around, and they eventually accumulate enough
to cause disk full errors.  (If a gc ever succeeded, I suspect these
files would go away, but that requires manual intervention).

I would appreciate any thoughts...  Thanks!

-- 
Sitaram