Time-Limited Error Recovery (TLER) is a solution designed by Western Digital that allows PATA and SATA hard disks to be used with RAID controllers. This feature will prevent a disk from being marked failed by limiting the time spent on correcting detected errors caused by vibrations during high loads. This feature reduces the chance of data loss, which happens when multiple disks fail while the RAID volume is in degraded mode. Western Digital's RAID edition hard disks come with this feature enabled by default, with their other disks having the option disabled by default or completely unsupported. TLER can be enabled or disabled using the tool WDTLER on a DOS bootdisk.
Western Digital states that this feature cannot be disabled. [1] However users and independed editors have have reported that this feature can be disabled. [2] [3] [4] [5] The tool allows this feature to be disabled by setting the values for read and write and 0 second. By default, Caviar Raid Edition comes with read disabled and write set to 7 seconds while both settings are disabled for Raptor hard disks.