Cobalt servers typically log activity for all web sites in a single centralized log file, which is then split into individual site log files each night by a program called logrotate. Under certain circumstances this log rotation process will cause a website's log file to be renamed and compressed before Urchin can process it. The result is that there will be no data in the Urchin reports for that day. To find out if the reason you have missing report data is because Urchin is unable to locate and process logs, you should examine the Urchin Scheduler history. Under Configuration->Scheduler->Task History, click on the status column for the appropriate task. If the log was unavailable to Urchin, you will see this message:
WARNING: (7025-646-367) Log file does not exist or is not readable.
Unless it is possible that there could be no activity for this website for some days, this message could mean that the log file was moved before Urchin was able to process it. To alleviate this problem, increase the disk quota for the site. The logrotation size parameter that determines if a log file is archived is calculated based on the site�s overall disk quota. So you can cause log rotation to be adjusted indirectly by increasing the disk quota for a site that exhibits this problem. To change the disk quota:
- In the Cobalt Administration interface, select Site Management. You are presented with a list of all the websites served by this system.
- Click the edit symbol to the right of a site that does not have report data. The Site Management screen for the site appears.
- Click General Settings or Site Settings as is appropriate for your system.
- Increase the Maximum Allowed Disk Space (MB) setting. The logrotation size parameter is calculated as 10% of this disk quota. Your current logrotation setting will be 10% of whatever is in this field. Determining how much to adjust the number is case dependent and should be based on the amount of traffic your site gets. A good place to start is to increase the number in this field by 50%, then make further adjustments as needed each day.
- Click the Save button when you are finished.
Note: On RaQ3 and RaQ4 systems, a patch from Cobalt is required to enable your Cobalt Administration GUI to correctly make the quota adjustment described above. Without the patch, adjusting the disk quota will have no effect on the logrotate size setting. The appropriate patches are:
- RaQ3: RaQ3-All-System-4.0.1-9447.pkg
- RaQ4: RaQ4-All-System-1.0.1-9447.pkg
Sometimes processing and rotation of the logs on your Cobalt system will halt completely. This is not the result of the Urchin installation or Urchin processing. This happens when the internal site usage statistics extracted by the Cobalt system fail in some way, which causes the rest of the logrotate mechanism to become inactive. Since Urchin has to wait until logrotate finishes its job, there is no data for Urchin to process in this case. Logrotate failures of this type are best fixed by making sure you have all the latest Cobalt patches installed on your system. In particular, the OS update patches that are pertinent to your Cobalt platform can alleviate this problem.