When a database dump fails, as seen in "20 items failed" on http://download.wikimedia.org/backup-index.html
then the dump script continues with the next database in turn. Apparently they often fail in groups. I guess this is because the failure doesn't depend on the database itself (e.g. svwiki) but on some other circumstance. When that circumstance is solved, all dumps succeed.
Right now (20080529), frwiki is being dumped. Previous successful dumps of frwiki were done on 20080514 and 20080420, http://download.wikimedia.org/frwiki/
The last successful dump of svwiki was made on 20080406, but the one on 20080425 failed, and the one on 20080524 was aborted, http://download.wikimedia.org/svwiki/
Hopefully, but only hopefully, the next svwiki dump will succeed in just a few days or weeks. But who knows. Maybe it too will be aborted and the next dump of frwiki will run instead.
What I want is the dump script to be rewritten so it prioritizes those databases (websites) that haven't been successfully dumped in a long time. It seems unfair that the French should have one every fortnight when us Swedes are waiting almost two months.
Other than this, I want the dumps to fail less often. Why do they fail? Has this been investigated? What can be done to help this?