From time to time, users ask if it would be safe to delete log files for the OASIS database, especially when the server is running critically low on disc space. In response to this, Ingen Software strongly urges users to truncate log file and store the truncated log on a safe local hard drive instead of deleting the log file altogether, as doing so can cause system failure. For more information on why maintaining log files is important, click here.
Understanding Sybase Technology and Log Files
OASIS uses SAP Sybase SQL Anywhere. This is a relational database that uses internal recovery technology, allowing databases to automatically recover during system failures. This system uses the following files:
- oasis.db- this is the OASIS database.
- oasis.log- this is the active log (recovery) file. This file is used by Ingen Software to restore your system if problems occur with the database.
- ######XX.LOG- these are inactive recovery files. Note: these files will always be named with six numbers, two letters, and the "log" extension.
When users open and view an OASIS transaction, the data is pulled from the oasis.db file. When users save a transaction in OASIS, the data is written to both the oasis.db and the oasis.log file. This "dual-write" process is important if a system failure occurs and data in the oasis.db file is corrupted. In response, the oasis.log file is automatically consulted by the database to correct the order.
However, the size of the oasis.log file will continuously grow. If a verified backup system is in the place, the oasis.log file should be truncated periodically. CAUTION: DO NOT DELETE THE LOG FILE. THIS WILL CAUSE DATABASE FAILURE.
Truncating the OASIS.LOG File
Before proceeding, please ensure the following statements are true:
- there are no other users operating OASIS
- this process is being performed by a user with administrative access
- an external USB hard drive is available. New users should assume 10 GB of disc usage the first year. At a bare minimum, the smallest the database will ever be is 1.5 times the size of the oasis.db file. 1TB USB drives can be purchased for under $100.
1. Confirm that you have a valid recent backup before proceeding. For more information, click here.
2. Navigate to the Configuration page.
3. Select "Software" from the drop-down list.
4. Select "Backup Transaction Log."
5. The "Question" window will appear, suggesting that users perform this action when there are no other users in OASIS.
6. Select "Yes" to confirm no other users are in OASIS and to launch the backup.
7. OASIS will begin backing up the transaction log.
8. When this process is complete, stop the OASIS database. For more information, click here.
9. Locate and open the OASIS database folder in your computer.
10. In the folder, a new "log" file with today's date will appear. Note: this file can be moved to create more space and manage file size.
11. Copy all files in the oasis database directory to an external USB drive.
12. Verify that the files copied before proceeding to step 13.
13. Remove all files from the OASIS database directory formatted with six numbers, two letters, and the extension ".log." CAUTION: DO NOT DELETE OASIS.DB OR OASIS.LOG.
14. Start the database and verify that transactions from the previous date are still on the server.
15. Place the USB drive in a bank safe deposit box or another secure location.