Last modified: 2013-01-24 21:25:36 UTC
We have many reports of "Error generating thumbnail: The source file for the specified thumbnail does not exist", which for some reason now are displayed as e.g. Error generating thumbnail The source file 'Bandera_de_Castrillón.svg' does not exist. https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Bandera_de_Castrill%C3%B3n.svg/500px-Bandera_de_Castrill%C3%B3n.svg.png This seems to affect all uploads in some specific timespans, apparently unrelated to the migration, for instance https://commons.wikimedia.org/w/index.php?title=Special:ListFiles&dir=prev&offset=20130123114541&limit=30&user=DcoetzeeBot See: https://commons.wikimedia.org/w/index.php?title=Commons:Village_pump&oldid=88705842#.22Error_generating_thumbnail_.E2.80.93_The_source_file_for_the_specified_thumbnail_does_not_exist..22 https://en.wikipedia.org/w/index.php?title=Wikipedia:Village_pump_%28technical%29&oldid=534688091#Images_not_rendering Aaron is debugging this right now.
The problem was the mixed use of two different memcached clusters (tampa/eqiad) caused by switching apaches to eqiad but leaving some scaling in tampa (such as in the 404 handler in swift). Scalers have been switched to eqiad so the same memcached cluster is now used consistently. The broken thumbnails I was looking at were fixed after that.
