Appendix A - Setting Read-After-Write Verification
Bad block remapping is the process of detecting damaged disk blocks and reassigning these blocks to other areas on the disk so that they are not used in the future. The process of verifying the integrity of data after it has been written to disk is called read-after-write verification.
If verification indicates that data in a specific block is defective, the operating system remaps the entire block to a new area on the disk and transfers the data to the remapped block.
Note: The operating system remaps bad blocks even if you turn off read-after-write verification.
Turning Off Read-After-Write Verification
Because the operating system must access the disk twice when verifying data written to disk, verification slows server performance. Since most SCSI disks perform their own bad block remapping, you can safely turn off read-after-write verification for servers that use SCSI disks.
To Turn Off Read-After-Write Verification
1. From the Operator Menu, choose System Maintenance. The System Maintenance menu appears.
2. Choose Configure/Diagnose Server. The BANYAN Server Configuration Menu appears.
3. Choose Configure File System. The Configure File System screen appears.
4. Choose TOGGLE Read-After-Write Verify. This function toggles verification on and off. The current setting appears in the lower left of the screen.
5. Press ENTER to change the setting. The screen displays the new setting.
6. Do one of the following:
- Choose SAVE Changes and Exit or press F10 to save your change. A message appears, indicating that you must reboot the server for the change to take effect. The Banyan Server Configuration Menu then appears.
- To cancel the procedure without saving your change, choose ESCAPE Without Saving or press ESC. A message appears, indicating that you have aborted the reconfiguration. The Banyan Server Configuration Menu then appears.
7. Reboot the server when you are ready for the change to take effect.