Log-structured file system for disk drives with shingled writing
View Patent ↗Data is written to a hard disk drive using shingled writing principles, i.e., each data track is partially overwritten when an immediately contiguous data track is written. One or more contiguous data tracks establish a band, and a band establishes a respective segment in a log-structured file system.
1. A data storage system comprising:
disk means for storing data;
means for writing data to the disk in tracks and bands, wherein at least two tracks establish a band and wherein at least some bands are shingled; and
means for controlling the means for writing, the means for controlling using a log means for establishing a file system, wherein the log means uses a virtual address table (VAT) to remap sectors as required for shingled track writing.
2. The system of claim 1 , wherein at least some bands include at least three contiguous tracks.
3. The system of claim 1 , wherein the means for writing is configured for perpendicular recording.
4. The system of claim 1 , wherein the log means uses an error correction code (ECC) block size larger than a physical sector size of the disk means, a cumulative ECC parity state between successive partial writes of an ECC block being retained.
5. The system of claim 1 , wherein the VAT maps virtual sector locations to actual sector locations.
6. The system of claim 1 , wherein the VAT is stored on the disk means in at least one of: a location with non-overlapping tracks where random access writes can be performed, and a region with shingled written bands, using a log structured storage approach.
7. A redundant array of independent disks (RAID) system comprising a RAID controller and a plurality of hard disk drives, each disk drive including at least one storage disk and at least one drive controller reading data from and writing data to the disk, wherein the drive controller for each disk drive is coupled to the RAID controller, the drive controller for each drive writing data in shingled bands using a log-structured file system.
8. The RAID system of claim 7 , wherein at least some bands include at least three contiguous tracks.
9. The RAID system of claim 8 , wherein the disk drives are configured for perpendicular recording.
10. The RAID system of claim 8 , wherein the log-structured file system uses an error correction code (ECC) block size larger than a physical sector size of a disk, a cumulative ECC parity state between successive partial writes of an ECC block being retained.
11. The RAID system of claim 8 , wherein the log-structured file system uses a virtual address table (VAT) to implement shingled track writing.
12. The RAID system of claim 11 , wherein the VAT maps virtual sector locations to actual sector locations.
13. The RAID system of claim 11 , wherein the VAT is stored on the disk in at least one of: a location with non-overlapping tracks where random access writes can be performed, and a region with shingled written bands, using a log structured storage approach.
14. The RAID system of claim 11 , wherein the RAID controller accesses the VAT to remap sectors as required for shingled track writing.