Seagate’s Corvault storage system offers over 2.1 petabytes of storage space in a single rack slot. It contains 106 server hard drives from the Exos series, each with a capacity of 20 TB. Typically, a few drives would fail over the five-year warranty period, but the Corvault has self-healing functions that reduce the need for replacements. By autonomously regenerating defective drives, the Corvault minimizes data loss.
One common issue that leads to disk replacements is a defective head or disk surface. However, since a 20 TB hard drive contains 10 disks and 20 heads, only 5% of the capacity is affected by such defects. The storage controller removes the faulty drive, tests its components, and reports the available capacity to the controller. The storage software, running on redundant hardware controllers, reintegrates the drive back into the system. This process, known as Autonomous Drive Regeneration (ADR), maintains the non-defective capacity of a hard drive.
To ensure data redundancy, the Corvault distributes data across all drives using erasure coding. This reduces the likelihood of data loss. Seagate refers to this technology as Autonomic Distributed Allocation Protection Technology (ADAPT). In the event of a defect, the storage software integrates a reserve hard drive to restore the data from the redundant ones. Rebuilding after a disk defect takes only a few hours due to the reduced amount of data.
Seagate plans to implement ADR in its Exos hard drives with 18 TB of storage space. In a second generation, only the defective portion of a drive will be removed from the pool, rather than the entire drive. Seagate also aims to offer 50 TB drives using Heat Assisted Magnetic Recording in 2026, further increasing the total capacity of the Corvault system.
In terms of performance, the Corvault achieves up to 14 GB/s read and 12 GB/s write speeds according to the data sheet. However, during testing, the system reached a maximum of 7.5 GB/s, likely due to the SAS connection to the server. The measurements also demonstrated high IOPS, reaching over 70,000 without optimizations.
Seagate estimates that customers can expect to pay around $30 per TB for the Corvault system. This price is lower than that of traditional JBOD systems without ADR technology. Seagate emphasizes the cost savings in operation, as the Corvault reduces the need for service technicians and minimizes e-waste by avoiding regular drive replacements. Additionally, fewer drives are required overall, leading to a lower carbon footprint.
Disclosure: Seagate covered the travel and accommodation expenses for the author.
Sources:
– https://www.heise.de/tests/Seagate-Corvault-18-TB-wieder-verwendbar-5192700.html
