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What every T24 Engineer should know about File Sizing

Reading and writing data to large files is often a performance bottleneck, which is also true for the T24 core banking system. Usually, it would help if you made file resizing part of your housekeeping or operational activities.

Then, your database can overgrow, and your T24 files will increase simultaneously.

Some elements require special attention, such as the directory and the COMO directory.


To reduce the directory size, kindly use the appropriate methods for &HOLD&, &COMO&, &PH&, EXCEPTION.LOG.FILES, OFS.REQUEST.DETAIL, PROTOCOL files.

HOLD: It contains reports generated during COB and will be cleared based on your REPORT.RETENTION configuration.

COMO: This directory contains logs for each action such as COB and UPDATE logs. Make sure that you clear this directory from time to time.

PH: These are informative purpose logs and must be cleaned up manually or as part of your housekeeping jobs.

EXCEPTION.LOG.FILES: This directory contains essential details about errors during end-of-day processing. Make sure that you review and clean these files regularly.

Here are a few more helpful hints you should know

  1. SYSTEM.CLEAR.FILES will remove all sensitive data

  2. Frequent backup and deleting the COMO files reduce the disk space and improve your read and write activities.

  3. From time to time, you should execute CHECK.T24.FILES and resize them. There is a utility in jBASE by the name "jrf" which simplifies resizing files in jBASE.

  4. The Frequency of resizing depends on the database growth.

  5. Resizing can be done through formal enquiry and finding the resized files.

  6. During resizing of jbase files using RESIZE.GLOBUS, the system can prompt a "probably in use" message, which indicates that the file was not resized. Restricting certain activities can be used to avoid errors.

  7. Convert files to JR on a case-to-case basis

  8. J4 file modulo calculation and resizing and file corruption information

  9. Resize the base file using jrf commands

Avoid file corruption

File corruption can eventually block your T24 core banking engine. Based on our experience such a file related corruption can occur in the following situations:

  • Power failure

  • Network down

  • Server reboot during updates

  • Kill command executed during updates

  • File size beyond 2 GB

Our next blog post will share insights about necessary timeout settings in T24. Also, we will start T24 performance tuning workshops for our customers soon. So follow us to receive more updates about this topic.

Keep up the great work! Happy Performance Engineering!

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