After having used piwik successfully for about a year now, we decided to set cron to manage the archiving of reports instead of on user visit. We’ve got around 100 sites with fairly low traffic; although a number may reach 100 hits a day; small potatoes in comparison to some of the posters on this forum. We did this prior to the 1.6 upgrade and it seemed to be quite successful.
We run PHP 5.3.x via Apache 2/mod_fcgid on a Debian server and it works really well. We made some tweaks to ensure that the archive process ran successfully (details in this gist) by removing limits on execution time in php.ini and in the httpd vhost configuration.
After a few days we noticed that February’s data was set at 0 for 25% of our sites. I manually ran archive.php and it was still 0 until i ran with the --force-all-sites flag. This repeated the following day, and so on, for the last 7 days. We have since upgraded to 1.7 in the hope that it may resolve the issue, but 'twas of little or no avail.
Does anyone have any idea? I have since started logrotating so that I can try and spot any errors in the logs but haven’t found any evidence of errors.