User accessible data on a hard disk drive is organized into logical blocks called sectors. Sectors are, essentially, the amount of data that can be read from, or written to, a disk drive. Since the 1980s, sectors have almost universally been a 512-byte format, and operating systems, computer hardware and applications have been developed presuming 512-byte sectors to keep track of all the data files stored on the disk drive.
More recently though, the disk drive storage capacities have been increasing exponentially it seems with each new drive generation – from gigabytes to terabytes today. The result is that a single sector now represents a small fraction of the storage capacity. While this extra granularity may seem helpful, it actually results in less efficient communication between a computing architecture and storage media, and more concerns for maintaining data integrity. Operating systems and applications now typically communicate in blocks that are several times larger than the 512-byte sector size. When writing data into a sector, each sector will have some overhead in the form of sector identification and data protection code. Clearly, communication between the host system and storage device would benefit from using a larger sector size, as this would result in a smaller percentage of overhead and allow for continued improvements in data protection.
Disk drive manufacturers now support a larger, standard 4K-byte sector size, variously referred to as "4K native", "Advance Format", "AF" or "4Kn". Instead of the traditional 512-byte sectors, these drives are formatted to use 4K-byte sectors, which can contribute to an increase in drive efficiency and performance. However, the challenge is that operating systems, software applications, and computer hardware often make assumptions about disk sector size. So, server and storage system builders need to ensure that their platform is fully able to support 4Kn disk drives.
Things to think about: compatibility between the disk drives, host bus and RAID adapters, applications and operating systems.
Disk Drives: Toshiba has been working with many 3rd party solution providers in recent years on recognizing the potential of 4Kn technology and enabling the advancement of solution testing and compatibility. Today, Toshiba offers a full suite of 4Kn hard disk drives options.
Host bus and RAID Adapters: Fortunately, there are many good options available for storage connectivity. For example, certain manufacturers of storage connectivity products, such as ATTO Technology, have recently stated1 that their SAS/SATA Host and RAID adapters are fully compatible with industry standard disk drives that support 512-byte, 512 emulation (aka 512e - which emulates 512-byte sectors), and 4Kn.
Applications: Some legacy applications still expect 512-byte blocks on the storage media; however, they are slowly being updated to accommodate 4K-byte sector formats. Check with your application vendors regarding support for 4Kn formatting.
Operating Systems2 : Recent operating systems have 4Kn support; Linux® 2.6.31 or later3, And Microsoft® Windows 8, 8.1 and Server 2012 supports 4Kn sector sizes4.
Once again, hard disk drives and the IT industry have experienced change, adapting to achieve more efficient, higher storage capacities, more efficient host to device data communication, and reliability. From as early as 20035, Toshiba was among the handful of remaining hard disk drive manufacturers to endorse, design, and produce disk drives with the longer data sector format, and continues to work with a variety of system and application vendors on adoption of 4Kn sector technology. Concurrently, the IT ecosystem continues working together to ensure improvements in technology.
1ATTO Tech: https://www.attotech.com/software/files/techpdfs/TechSheet_ESAS12GbHBA.pdf and
https://www.attotech.com/software/files/techpdfs/TechnicalSpecifications_ESAS6GbHBA.pdf and
https://www.attotech.com/software/files/techpdfs/TechnicalSpecifications_ESAS6GbRAID.pdf
2"Information regarding 4Kn support is based on product information made publicly available by Microsoft and Linux. Toshiba makes no representation regarding the accuracy of such information."
3Linux:http://kernelnewbies.org/Linux_2_6_31#head-5a6f57dc036c513bd60426fba4c6f5c13eb6cee1 and
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=e1defc4ff0cf57aca6c5e3ff99fa503f5943c1f1
4Microsoft: http://blogs.msdn.com/b/b8/archive/2011/11/29/enabling-large-disks-and-large-sectors-in-windows-8.aspx and
http://www.microsoft.com/en-us/server-cloud/products/windows-server-2012-r2/
5IDEMA: http://www.idema.org/?page_id=2369
The views expressed on this post are my own and do not necessarily reflect the views of Toshiba America Electronic Components, Inc. (TAEC), Toshiba Corporation, ATTO Technology, Inc., Linux, or Microsoft. Linux is a registered trademark of Linus Torvalds . Microsoft and Windows are either registered trademarks or trademarks of Microsoft Corporation in the United States and/or other countries. Any other trademarks, trade names, service marks, and logos referenced herein belong to their respective companies.