Comment One Form of logging is not enough (Score 1) 225
I work on my company's billing system and we use both database and file logs. We process millions of transactions a month so it's important to not only have a detailed audit trail of every transaction but also be able to keep track of any errors and be able to recover transactions from logs in the case of something unexpected happening.
For file logs we use Log4Net and I recommend it. It allows us to specify log statements as Warning, Debug, Error, or Fatal. We have it set up so that all types are logged in the file while any Error or Fatal log statement is emailed to the engineers so we can immediately look into the situation. I don't believe in having too many log statements as it does nothing but make finding useful information difficult. As a general rule we log as much information as possible about each transaction as it comes in and out of each part of our system as well any major changes to that data that come from a part of processing it.
Database logs are extremely useful because they can be queried unlike file logs. This makes finding the information you need much easier. In our case however the db logs only contain information about the transaction and not the processing of it. Therefore both the db and file logs are necessary.
Having two types of logs also acts as a fail safe. If our db goes down we still have file logs. If there is no trace of something in the file logs we can check the db.
Now with this level of logging comes other issues such as archiving logs and dealing with db log tables that are too big but that's a topic for a whole other discussion.
For file logs we use Log4Net and I recommend it. It allows us to specify log statements as Warning, Debug, Error, or Fatal. We have it set up so that all types are logged in the file while any Error or Fatal log statement is emailed to the engineers so we can immediately look into the situation. I don't believe in having too many log statements as it does nothing but make finding useful information difficult. As a general rule we log as much information as possible about each transaction as it comes in and out of each part of our system as well any major changes to that data that come from a part of processing it.
Database logs are extremely useful because they can be queried unlike file logs. This makes finding the information you need much easier. In our case however the db logs only contain information about the transaction and not the processing of it. Therefore both the db and file logs are necessary.
Having two types of logs also acts as a fail safe. If our db goes down we still have file logs. If there is no trace of something in the file logs we can check the db.
Now with this level of logging comes other issues such as archiving logs and dealing with db log tables that are too big but that's a topic for a whole other discussion.
