FAQ

Common Names
Reported Logical
Sector Size
Reported Physical
Sector Size
Windows Version with
Support
512-byte Native, 512n
512 bytes
512 bytes
All Windows versions
Advanced Format, AF,
512e, 512E, 512-byte
Emulation
512 bytes
4096 bytes
Windows Server 2012
Windows Server 2008
R2 w/ MS KB 982018
Windows Server 2008
R2 SP1
Windows Server 2008
w/ MS KB 2553708
Advanced Format
native, AFn, 4K Native,
4Kn*
4096 bytes 4096 bytes Windows Server 2012
(4K data disks are
supported and as boot
disks in UEFI mode)
While not stressed in the preceding table, Windows Server 2003, and Windows Server 2003 R2 do not
support 512e or 4Kn media. While the system may boot up and be able to operate minimally, there may be
functionality issues, data loss, or sub-optimal performance. Thus, Dell strongly cautions against using 512e
media with legacy Windows operating systems such as Windows Server 2003.
Common Names
Reported Logical
Sector Size
Reported Physical
Sector Size
Linux Version with
Support
512-byte Native, 512n
512 bytes
512 bytes
All Linux versions
Advanced Format, AF,
512e, 512E, 512-byte
Emulation
512 bytes 4096 bytes RHEL 6.1 *
SLES 11 SP2 **
Ubuntu 13.10
Ubuntu 12.04.4
Advance Format native,
AFn, 4K Native, 4Kn
4096 bytes 4096 bytes RHEL 6.1 *
SLES 11 SP2 **
Ubuntu 13.10
Ubuntu 12.04.4
3. What are 512 emulation HDD performance issues and potential data integrity
risks?
As the 512e HDD has a 4K bytes physical sector, the internal HDD read and write functions are performed
on one physical sector (4K bytes) at a time or as a group of eight logical sectors (512 bytes) at a time. As
the legacy host performs data transfer at 512 bytes boundary, any of the write data could start and end at
the beginning, in the middle or at the end of the 4K physical sector. When the data starts or ends in the
middle of the physical sector, it is called misaligned data. On misaligned data, the 512e HDD must perform
READ-MODIFY-WRITE (RMW) functions to complete the write operations. Therefore, 512e HDD suffers
significant performance loss (50%) in the random writes, misaligned data operations. In addition, a sudden
power loss during RMW operation could corrupt the physical sector causing data loss or corruption on
adjacent logical sectors within the affected physical sector. The host will not be aware of these
corruptions on the adjacent logical sectors since they were not part of the data transfer during the
emergency power loss condition.
6 4K Sector HDD FAQ