RAID timeout parameter accessibility request
Title: RAID timeout parameter accessibility request
Hi everyone, I hope I'm in the right list for posting this.
My request is about the "md" module (multiple disk Software RAID driver).
As you might know, if you install and use a "desktop edition" hard drive in a RAID array, the drive may not work correctly. This is caused by the normal error recovery procedure that a desktop edition hard drive uses : when an error is found on a desktop edition hard drive, the drive will enter into a deep recovery cycle to attempt to repair the error, recover the data from the problematic area, and then reallocate a dedicated area to replace the problematic area. This process can take up to 120 seconds depending on the severity of the issue.
The problem is that most RAID controllers allow a very short amount of time (7-15 seconds) for a hard drive to recover from an error. If a hard drive takes too long to complete this process, the drive will be dropped from the RAID array !
Of course there are "RAID edition" hard drives with a feature called TLER (Time Limited Error Recovery) which stops the hard drive from entering into a deep recovery cycle. The hard drive will only spend 7 seconds to attempt to recover. This means that the hard drive will not be dropped from a RAID array. But these "special" hard drives are way too expensive IMHO just for a small firmware-based feature.
There would be an easy way to allow users to use "ordinary" hard drives in a Debian software-controlled RAID array. So here's my request : I suppose there is a parameter that handles the default timeout before a drive is dropped from the RAID array. I don't know if this parameter is hardcoded, but it would be nice if it was user-adjustable. This way, we could simply set up this parameter to 120 seconds or more (instead of 7-15) and we wouldn't have any more problems with using desktop "edition hard" drives in a RAID array.
What do you think ? Can it be done in a future build ?
Many thanks in advance & Best regards.
Jose
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