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Seagate ST31000640SS, ST3750630SS, ST3500620SS Deferred Auto-Reallocation, Idle Read After Write

Models: ST31000640SS ST3500620SS ST3750630SS

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7.6Deferred Auto-Reallocation

Deferred Auto-Reallocation (DAR) simplifies reallocation algorithms at the system level by allowing the drive to reallocate unreadable locations on a subsequent write command. Sites are marked for DAR during read oper- ations performed by the drive. When a write command is received for an LBA marked for DAR, the auto-reallo- cation process is invoked and attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

This is in contrast to the system having to use the Reassign Command to reassign a location that was unread- able and then generate a write command to rewrite the data. DAR is most effective when AWRE and ARRE are enabled—this is the default setting from the Seagate factory. With AWRE and ARRE disabled DAR is unable to reallocate the failing location and will report an error sense code indicating that a write command is being attempted to a previously failing location.

7.7Idle Read After Write

Idle Read After Write (IRAW) utilizes idle time to verify the integrity of recently written data. During idle periods, no active system requests, the drive reads recently written data from the media and compares it to valid write command data resident in the drives data buffer. Any sectors that fail the comparison result in the invocation of a rewrite and auto-reallocation process. The process attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

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Barracuda ES.2 SAS Product Manual, Rev. E

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Seagate ST31000640SS, ST3750630SS, ST3500620SS manual Deferred Auto-Reallocation, Idle Read After Write
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ST31000640SS, ST3500620SS, ST3750630SS specifications

Seagate has been a leading name in the storage industry for decades, and its range of enterprise-class hard drives showcases advanced technologies and robust performance. The Seagate ST3750630SS, ST3500620SS, and ST31000640SS are three notable models that cater to the demands of data centers and enterprises. Each model is designed with specific features that enhance reliability and efficiency, making them suitable for various applications.

The Seagate ST3750630SS is a 750GB 15K RPM Serial Attached SCSI (SAS) drive. It boasts a high-performance architecture that allows for fast data transfer rates, making it ideal for high-load environments such as transaction processing and video streaming. This drive features an MTBF of 1.6 million hours, ensuring minimal downtime due to failures. It also employs advanced error recovery and data protection mechanisms, including error correction codes (ECC), to maintain data integrity.

Meanwhile, the ST3500620SS offers a capacity of 500GB with a spinning speed of 15K RPM as well. This drive utilizes the SAS interface, providing users with improved bandwidth and connectivity compared to traditional SATA drives. The ST3500620SS is designed with a focus on high availability, featuring a robust design that supports multiple workloads simultaneously. Its quick access times enhance overall system performance, making it a preferred choice for high-performance computing applications.

The ST31000640SS is another enterprise-class offering, delivering 1TB of storage capacity. Like its counterparts, this drive operates at 15K RPM and utilizes the SAS interface, facilitating fast data processing and retrieval. It also incorporates a dual-port design which allows for redundancy and failover capabilities. This feature is critical in enterprise environments where data access and uptime are paramount. The drive's design is optimized for durability and longevity, best suited for environments that require 24/7 operation.

All three Seagate drives feature advanced technologies such as dual-stage actuators and thermal write technology, ensuring improved read and write performance, along with reduced power consumption. Additionally, they are built to endure the rigors of enterprise workloads, including heavy I/O operations and high access demands.

In summary, the Seagate ST3750630SS, ST3500620SS, and ST31000640SS are exemplary models that reflect the company’s commitment to quality and performance in enterprise storage solutions. With their high speeds, reliability, and extensive features, these drives are well-equipped to meet the challenges of modern data-driven environments.