3Ware 9500S-12MI User Guide - Page 175

AEN Messages in a degraded array situation. For redundant arrays such as RAID 1, 10, 50, and 5, the 3ware RAID controller essentially has two copies of the users data available. If a read command to a sector on a disk drive results in an error, it reverts to the redundant copy in order to satisfy the host's request. At this point, the 3ware RAID controller has a good copy of the requested data in its cache memory. It will then use this data to force the failing drive to reallocate the bad sector, which essentially repairs the sector. When a sector repair occurs, the user is notified by this AEN. The fact that a sector repair AEN has been sent to the user is an indication of the presence of grown defects on a particular drive. While typical modern disk drives are designed to allow several hundred grown defects, special attention should be paid to any drive in an array that begins to indicate sector repair messages. This may be an indication of a drive that is beginning to fail. The user may wish to replace the drive, especially if the number of sector repair errors exceeds 3 per month. AEN 024h AEN_SBUF_FAIL The 3ware RAID controller, as part of its data integrity features, performs diagnostics on its internal RAM devices. Once a day, a non-destructive test is performed on the cache memory. Failure of the test indicates a failure of a hardware component on the 3ware RAID controller. This AEN is sent to notify the user of the problem. Contact Technical Support for a replacement controller. AEN 025h AEN_LOST_CACHED_WRITE To improve performance, this 3ware RAID controller features caching layer firmware. For write commands this means that it acknowledges it has completed a write operation before the data is committed to disk. If the 3ware RAID controller can not commit the data to the media after it has acknowledged to the host, this AEN is posted to the user. Typically, the LOST CACHED WRITE notification would be an indication of a catastrophic failure of the drives in the array, such as loss of power to multiple drives in an array. AEN 026h AEN_DRIVE_ECC_ERROR This AEN may be sent when a drive returns the ECC error response to an 3ware RAID controller command. The AEN may or may not be associated with a host command. Internal operations such as Background Media Scan post this AEN whenever drive ECC errors are detected. Drive ECC errors are an indication of a problem with grown defects on a particular drive. For redundant arrays, this typically means that dynamic sector repair would be invoked (see AEN 023h). For non-redundant arrays www.3ware.com 169