Time Limited Error Recovery

Samuel Williams Tuesday, 11 August 2009

I recently read about TLER on Western Digital drives. Apparently they charge more for RAID drives with a 7-second TLER. This is interesting to me since I deal with data storage and enclosures.

Here are some more details about TLER:

Basically, the problem as I interpret it is that a non-fatal error may result in the drive dropping from a RAID because the drive spends too much time trying to recover from the error. In most kinds of RAID, the failure tolerance is 1 drive - if all drives have TLER disabled, it may result in the self-destruction of the entire RAID due entirely to non-fatal errors. Rebuilding a failed disk in a RAID5 is not a quick process and can put a lot of stress on other drives.


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