10.0Defect and error management

Seagate continues to use innovative technologies to manage defects and errors. These technologies are designed to increase data integrity, perform drive self-maintenance, and validate proper drive operation.

SCSI defect and error management involves drive internal defect/error management and SAS system error considerations (errors in communications between the initiator and the drive). In addition, Seagate provides the following technologies used to increase data integrity and drive reliability:

Background Media Scan (see Section 10.4)

Media Pre-Scan (see Section 10.5)

Deferred Auto-Reallocation (see Section 10.6)

Idle Read After Write (see Section 10.7)

The read error rates and specified storage capacities are not dependent on host (initiator) defect management routines.

10.1Drive internal defects/errors

During the initial drive format operation at the factory, media defects are identified, tagged as being unusable, and their locations recorded on the drive primary defects list (referred to as the “P’ list and also as the ETF defect list). At factory format time, these known defects are also reallocated, that is, reassigned to a new place on the medium and the location listed in the defects reallocation table. The “P” list is not altered after factory formatting. Locations of defects found and reallocated during error recovery procedures after drive shipment are listed in the “G” list (defects growth list). The “P” and “G” lists may be referenced by the initiator using the Read Defect Data command.

Details of the SCSI commands supported by the drive are described in the SAS Interface Manual. Also, more information on the drive Error Recovery philosophy is presented in the SAS Interface Manual.

10.2Drive error recovery procedures

When an error occurs during drive operation, the drive, if programmed to do so, performs error recovery procedures to attempt to recover the data. The error recovery procedures used depend on the options previously set in the Error Recovery Parameters mode page. Error recovery and defect management may involve using several SCSI commands described in the SAS Interface Manual. The drive implements selectable error recovery time limits required in video applications.

The error recovery scheme supported by the drive provides a way to control the total error recovery time for the entire command in addition to controlling the recovery level for a single LBA. The total amount of time spent in error recovery for a command can be limited using the Recovery Time Limit bytes in the Error Recovery mode page. The total amount of time spent in error recovery for a single LBA can be limited using the Read Retry Count or Write Retry Count bytes in the Error Recovery mode page.

The drive firmware error recovery algorithms consist of 12 levels for read recoveries and five levels for write. Each level may consist of multiple steps, where a step is defined as a recovery function involving a single re- read or re-write attempt. The maximum level used by the drive in LBA recovery is determined by the read and write retry counts.

38

Constellation ES.2 SAS Product Manual, Rev. D

Page 46
Image 46
Seagate ST33000650SS manual Defect and error management, Drive internal defects/errors, Drive error recovery procedures

ST33000652SS, ST33000650SS, ST33000651SS specifications

The Seagate ST33000651SS, ST33000650SS, and ST33000652SS are high-performance enterprise hard drives designed for demanding storage applications. These models are part of the Seagate Constellation ES series, known for their reliability and performance in server and data center environments.

One of the most notable features of these drives is their capacity. The ST33000651SS and ST33000650SS offer a storage capacity of 3TB, providing ample space for data-intensive applications. The ST33000652SS enhances this with a larger storage option, ensuring that organizations can meet growing data demands without needing frequent upgrades.

These drives utilize a SATA 6Gb/s interface, which allows for high-speed data transfer. This increased bandwidth is essential for applications that rely on rapid access, such as virtualization, cloud computing, and database management systems. Additionally, the drives support Native Command Queuing (NCQ), which enhances performance by optimizing the order in which read and write commands are executed.

Reliability is paramount in enterprise environments, and Seagate addresses this with several technologies designed to minimize downtime. The ST33000651SS and its counterparts feature a 7200 RPM spindle speed, which not only delivers fast access times but also contributes to the overall durability of the drives. They also come with advanced error correction and data integrity features, which safeguard against data loss.

Another important characteristic of these drives is their low power consumption. Operating at an average power usage of 6.0W, they help reduce operational costs, particularly in large-scale deployments. This energy efficiency is essential for organizations looking to maintain sustainability while maximizing performance.

In terms of physical design, these hard drives are built to endure tough conditions typically found in data centers. They come in a standard 3.5-inch form factor, ensuring compatibility with a wide range of servers and storage enclosures. The robust design further enhances their lifespan, making them a sound investment for enterprise storage solutions.

In summary, the Seagate ST33000651SS, ST33000650SS, and ST33000652SS hard drives offer a compelling combination of high capacity, fast data transfer rates, and reliability. Their advanced technologies and energy-efficient design make them ideal choices for enterprises that require dependable and high-performing storage solutions in their IT infrastructure.