It was time to do updates on our sister server in Fairfax. Cleaned up appropriate old kernels and started on Drupal. Drush has become a critical tool for working on Drupal installations but we (Drush or me) stumbled on an update to Mollum.
Mollum is a filter which greatly reduces unwanted registration and other mischief. We has been coasting on mollom 7.x-1.1 and Drush was content to let us do that. An upgrade to 7.2.4 became available but drush did not pick it up automatically.
I picked out a somewhat larger hammer from the drush tool box "dl" or download and dropped the updated version on top of the old version. Worse than hitting my thumb, all but one of the sites in the "farm" were broken. After much googling and trial and error, I found a simple drush cc (cache clear) fixed the major problem. Since each site has its own database and cache, this had to be repeated for each site in the farm. Simple database updates fixed the minor problems.
Barb noted, that updates were the most hazardous part of the sys admin game. The battles are kind of neat as long as you win. Loki was playing with me since last night. I'll get to watch Doc Martin tonight.