While solid-state drives gradually transition to a PCIe physical interface with NVMe protocols, many applications still rely on the Serial Attached SCSI (SAS) technology. SAS is not near extinction as this week, the SNIA SCSI Trade Association Forum (STA) and the INCITS/SCSI standards organization introduced 24G+ SAS specifications explicitly aimed at next-generation HDDs and SSDs for hyperscale data centers.
“24G+ SAS is a big step forward for our industry and continues to demonstrate the value of SAS technology in the broader scope of data storage,” said Cameron T. Brett, Chair, SNIA STA Forum Board of Directors. “These key features span hard disk drives and SSDs and benefit hyperscalers, as well as traditional servers and storage. SAS and SCSI have been around for more than 30 years, delivering high performance, reliability, and scalability to data centers, and 24G+ SAS continues this taking data storage to the next level.”
The SAS specification received its latest performance upgrade to 2.4 GB/s in 2020, and the first drives with this interface are now on the market. The new 24G+ offers the same performance but adds five new features designed to enhance storage performance for traditional servers and hyperscale data centers.
The 24G+ SAS introduces the Command Duration Limits (CDLs) feature that controls HDD latencies to ensure that operations are completed within a specific timeframe to ensure efficiency and reliability in large-scale data environments. Another HDD-related feature is Format with Presets, which simplifies the management of HDDs that feature both CMR and SMR bands. It promises to reduce SKU count in data centers as typically hyperscalers have to use both CMR and SMR drives. The third HDD-specific feature, Logical Depopulation, identifies and removes faulty platters from data sets run in hyperscale applications.
In addition, the 24G+ SAS introduces Rebuild Assist for SSDs, a feature that helps discover unreadable logical blocks that need to be reconstructed from another source. Finally, the Persistent Connections feature optimizes performance by keeping connections open, eliminating the overhead associated with repeatedly opening and closing connections, which is advantageous for high-performance SSDs.
“Tried and true SAS technology continues its march forward, continuing to innovate data storage. 24G+ SAS provides features that help hyperscale and enterprise servers alike,” said Tom Coughlin, President of Coughlin Associates. “These enhancements promise improved efficiency and scalability, marking a notable progression in storage technology.”