Importance

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Abstract

Means and method are disclosed for managing data while a RAID system is recovering from a media error. As a media error occurs, the failing storage device is identified and the areas of failure are recorded in non-volatile storage. A data recovery process is then continued so that a maximum amount of data can be recovered even though more than one error has occurred. Areas of failure are recorded in both non-volatile memory on the RAID adapter card and also in reserved areas of remaining storage devices. The storage areas that have been detected to contain media errors are stripe number, stripe unit number and also down to the sector number level of granularity. When the user tries to access data, these records are checked. If there is an entry in the table for a stripe being accessed, the user will receive an error message. Although the user may lose a small portion of the data, the user is only presented with an error message instead of incorrect data. The table can also be checked on write operations. If an entire stripe of data is written successfully and that stripe is found in the table, the entry is removed. When a physical device is moved to another controller, the table is copied from the physical device being moved to the new controllers non-volatile memory so this information is not lost.

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First Claim