Sonnet Technologies Fusion RAID Configuration Tool and Utilities Operation Manual - Manual (Page 41)

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This chapter describes procedures to follow that may allow data
to be partially recovered when drives fail or become inaccessible
and cause a RAID group to go offline. Sonnet RAID controllers use ATTO Technologies’ DriveAssure™
technology to maintain error-free operation of RAID group
member drives. This includes features like Drive Initialization,
Media Scan, Parity Verify, Performance Monitoring, and
algorithms for latency and response management. Occasionally,
a drive will suffer a mechanical or fatal media error that makes
it unusable. A connection error may cause multiple drives to be
inaccessible, resulting in an array that cannot be accessed normally.
1.8 Recover Data from Offline RAID Groups
Definitions
RAID Group Status Definition
ONLINE The RAID group state is online, with all RAID group members available and fully operational.
DEGRADED The RAID group does not have full data protection. This occurs when a non-critical number of RAID
group members (drives) are unavailable, degraded or faulted (i.e., one member in a RAID 5 RAID
group, two in a RAID 6 RAID group, and so forth). On a read command to inaccessible drive(s), the
data is derived using redundancy or parity. A degraded RAID group may be initializing or rebuilding.
OFFLINE The RAID group’s data cannot be accessed because a critical number or drives have been faulted or
removed. For example, two or more drives in a RAID 5 RAID group have failed.
RECOVERY The RAID group is in basic data recovery mode. I/O may be limited to reads while in this state.
REC EXT The RAID group is in extreme data recovery mode, which returns data at all costs. I/O may be
limited to reads while in this state.
RAID Member Status Values Definition
ONLINE The drive is fully operational
DEGRADED Some of the drive’s data is not up to date
UNAVAILABLE Connection to the drive has been lost
FAULTED The drive has an unrecoverable error
Rebuild Status Values Definition
OK Data is up to date
REBLD The rebuild operation is in progress
A_INIT The advanced initialization operation is in progress
X_INIT The express initialization operation is in progress
MSCAN The media scan operation is in progress
Rebuild Status Suffixes Definition
…FAULTED The operation ceased due to an error
…HALTED The operation was stopped at the user request
…INTRUPTD The operation was interrupted
…% COMPL Percent completion for operation
WARNING: Anytime a RAID group goes offline, its
data integrity has been compromised. It is imperative
that data consistency checks and/or file system repair tools be
used to validate recovered data.