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Disk drive sector size

Sector size is an attribute of a disk drive (or SCSI LUN for an array-type device), which is set when the drive is formatted. Sectors are the smallest addressable unit of storage on the drive, and are the units in which the device performs I/O. The sector size is significant because it defines the atomic I/O size at the device level. Any multi-sector writes which VxVM submits to the device driver are not guaranteed to be atomic (by the SCSI subsystem) in the case of system failure.