EFFICIENT SUPPORT FOR DRIVES WITH DIFFERENT SECTOR ALIGNMENTS IN A RAID LAYOUT

摘要

In one embodiment, a method includes receiving an input/output (I/O) request for data that starts or ends at a location other than a physical sector boundary of the device. The method further includes reading, starting at a first physical sector boundary before a beginning location specified in the I/O request and ending at a second physical sector boundary after an ending location specified in the request.

主权项

1. A method comprising:
responsive to a write request to a redundant array of independent drives (RAID) with a plurality of drives, determining a RAID operation to fulfill the write request, and further determining a plurality of data items required to complete the RAID operation, wherein each data item comprises a data range on one of the plurality of drives, wherein the data range specified in each data item may start or end at a location other than a physical sector boundary of the drive specified in the data item; pre-reading at least one of the plurality of data items, starting at a first physical sector boundary at or before a beginning location specified in each corresponding data range and ending at a second physical sector boundary at or after an ending location specified in each corresponding data range; performing at least one of a modify operation to generate new parity or mirror data based on data from the write request and data from the pre-reads, a modify operation to overlay data from the write request onto the data from the pre-reads, and a modify operation to overlay data from the parity calculation onto data from the pre-reads; and writing any data item containing data from the write request starting at the first physical sector boundary and ending at the second physical sector boundary; wherein the plurality of disk drives are enabled to have one or a plurality of physical sector sizes.