HGST HUS724040ALS640 User Manual

HGST Ultrastar 7K4000 (SAS) Hard Disk Drive Specification
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20.15.3.3 Reassign Blocks Recovery
The Drive provides the capability to remove media defects without reducing capacity. If the mode parameter bit ARRE is
active, the Drive will automatically reallocate LBA's determined to be defective. For those LBA's where the error is unrecov-
erable or the initiator elects to not have the Drive automatically reallocate LBA's, the Drive will recommend reassignment of
the LBA.
Recovery from a failed reassignment consists of the following actions:
• Updating the defect descriptor to remove the LBA's that have been successfully reassigned and then retry the Reas-
sign Blocks command. The LBA contained in the Command Specific Information field of the Sense Data is the LBA
in the first defect descriptor that was not reassigned because of the failure. If the command failed because of an unre-
coverable read error other than those specified in the defect descriptor, add this LBA to the defect descriptor and retry
the command. Refer to Section 18.28, “REASSIGN BLOCKS (07)” on page 209, for additional information.
• If the retried Reassign Blocks (07) command completes successfully, returning to normal processing.
• If the retried Reassign Blocks (07) command fails, servicing the drive using the service guidelines recommended in
Section 20.15.1, “Drive Service Strategy” on page 302.
20.15.4 Nondata Error Recovery Procedure
The Drive will follow a logical recovery procedure for nondata errors. The initiator options for non-data errors are limited to
logging the error, retrying the failing command, or replacing the drive.
These recovery procedures assume the initiator practices data back-up and logs errors at the system level for interrogation by
service personnel.
20.15.4.1 Drive Busy
The Drive is busy performing an operation. This is not an error condition. The initiator can test for completion of the opera-
tion by issuing Test Unit Ready (00) (or media access) commands.
•If the Test Unit Ready (00) (or media access) command completes with Check Condition Status then issue a Request
Sense (03)
- If the specified recovery procedure for the sense data is for a condition other than drive busy, follow the recovery
procedure for the condition reported.
- If the specified recovery procedure for the sense data is for a drive busy condition, then continue re-issuing the Test
Unit Ready (00) and Request Sense commands for the duration of a media access time-out or until the drive returns
Good Status.
- If the drive has been busy for longer than the limit specified in Section 20.14, “Command Time out Limits” on
page 300, then service the drive using the service guidelines recommended in Section 20.15.1, “Drive Service
Strategy” on page 302. Otherwise return to normal processing.
•If the Test Unit Ready (00) (or media access) command completes with Good Status, then return to normal process-
ing.
20.15.4.2 Unrecovered Drive Error
The initiator should retry the failing command.
1. If the retry of the failing command completes with Good Status or recovered Sense Key, follow the recovery procedure
in Section 20.15.4.3, “Recovered Drive Error” on page 306.
2. If the retry of the failing command completes with hardware error sense, verify there is no outside cause (e.g., power
supply) for the failure, then retry the failing command.
a. If the retry of the failing command completes with Good Status, follow the recovery procedure in next Section
20.15.4.3, “Recovered Drive Error” on page 306.
b. If the retry of the failing command completes with Recovered sense or Hardware error sense, then service the drive
using the service guideline recommended in Section 20.15.1, “Drive Service Strategy” on page 302.

HGST HUS724040ALS640 Specifications

General

Brand	HGST
Model	HUS724040ALS640
Category	Storage
Language	English