Limiting the recovery time allows for improved error handling in hardware or software RAID environments.
Modern hard drives feature an ability to recover from some read/write errors by internally remapping sectors and performing other forms of self-test and recovery.
This is a long process, degrades performance, and if more drives fail under the resulting additional workload, it may be catastrophic.
If the drive itself is inherently reliable but has some bad sectors, then TLER and similar features prevent a disk from being unnecessarily marked as 'failed' by limiting the time spent on correcting detected errors before advising the array controller of a failed operation.
The array controller can then handle the data recovery for the limited amount involved, rather than marking the entire drive as faulty.
Enabling TLER seeks to prevent this by interrupting error correction before timeout, to report failures only for data segments.
[5] For hard drives that implement this interface, the smartctl utility (part of the smartmontools package) can be used to change the error-recovery timeout via -l scterc.
The utility works on and makes changes to all compatible Western Digital hard disk drives connected to the computer.
Western Digital claims that using the WDTLER.EXE utility on newer drives can damage the firmware and make the disk unusable.