Missing add-on usage data for 2012-04-20 through 2012-04-22

There was a failure of the logging daemon for the versioncheck.addons.mozilla.org site which prevented logs from being written for the duration of 2012-04-20 19:00 Pacific through 2012-04-22 14:00 Pacific.
Add-on download metrics are unaffected, but the add-on usage metrics for those dates are not available and cannot be recovered.

This failure was not detected quickly because a monitoring alert failed to function properly, and the Metrics team’s processing of the log data was delayed due to the datacenter migration of last week. When back-processing of the data caught up to the missing data, the Metrics team alerted IT to the problem and they quickly corrected it.