SummaryThe Exinda has various levels of logging that can be turned on or turned off depending on user preferences, and each one has benefits and drawbacks.
OverviewOn an Exinda appliance, messages (both core and process) are relayed through the Linux messaging system. Like in most logging in technology, it is possible to change the level of it to various granularities in order to get a complete (or less critical) view of what is going on in the device. This can be used for general user knowledge or for troubleshooting purposes. The 9 levels are as follows:
- Off: This level shuts all logging features off and nothing will be recorded no matter what happens in the system. This includes items like the boot sequence and status of the device.
- Emergency: This is the 'lowest' level of logging, which will only record log events that have an 'EMERGENCY' flag. This is reserved for things that make the kernel of the Exinda unusable.
- Alert: This level of logging shows Emergency logging as well as the ALERT level. An 'Alert' message comes when system action needs to be taken, for example if hardware is about to shut down.
- Critical: This level of logging shows the above plus CRIT messages, messages that indicate there's a critical condition (or error) in the system that should be addressed. Critical errors occur when processes can't communicate, or an unexpected shutdown was found. These messages indicate something needs to be done immediately.
- Error: This level of logging shows the above plus ERR messages, typical failures of processes. ERR messages indicate an error with something; it can be as innocent as a message logged when a configuration change isn't possible or when a process fails in its task but can recover on its own.
- Warning: This level of logging shows the above plus WARNING messages, warnings to the end user. These warnings indicate that a problem might exist or that a setting might not be optimal, but does not requier immediate attention.
- Notice: This is the default level of logging, it shows the above plus NOTICE messages. Notice level logging shows the general process of the Exinda, including when things start and end and the general flow of the Exinda. Success messages are usually sent as Notices to keep an audit trail of behaviour.
- Info: This level of logging shows the above plus INFO messages. This message system is a more 'low level' logging system in that multiple info messages can be sent per operation.
- Debug: This is the 'lowest' level of logging which shows all messages, including DEBUG messages. Debug messages are put in by developers for explicitly troubleshooting problems and can show hardware dumps and step by steps into what a process is doing at each moment.
Note that as the list is traversed and more logging is shown, it will increase the strain on system resources due to more constant writing in the system logs and requiring the processes to send more information, which will in turn increase the amount of HDD Input/Output and RAM usage. If your box is already heavy on system resources, keeping the device at a Notice level or higher is best practices; turning the logging down to Info or Debug level will hurt performance of the box.