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I've never heard about SMR before. I wonder - does it mean that a write to one area must be done in multiple disk rotations? Ie: if a sequential write to one fi

by majke 11y ago

I've never heard about SMR before. I wonder - does it mean that a write to one area must be done in multiple disk rotations? Ie: if a sequential write to one file be aggregated into a single location on the disk or will it be spread around the whole plate. Just wondering how a software utilizing this should behave. http://www.storagereview.com/what_is_shingled_magnetic_recording_smr http://www.storagereview.com/what_is_shingled_magnetic_recor... https://en.wikipedia.org/wiki/Shingled_magnetic_recording https://en.wikipedia.org/wiki/Shingled_magnetic_recording

codemac 11y ago
Heads up - if you've bought a high density disk recently, it's probably SMR internally anyways. A write to one area can be done in a single disc rotation, as long as it's sequential. SMR disks added what are called ZBC, Zoned Block Commands to the SCSI spec. The disk itself exposes the ability to interact with zones several ways: - REPORT ZONES - What zones there are, how many, what type, and state of the zone. - OPEN / CLOSE / FINISH ZONE - zone write state management So essentially, it's like a drive exposes ~8 files, opened with O_APPEND, and you have to manage how you stripe your writes between those files to handle your workload. Your disk can also have zones that aren't shingled, but those seem to have been fairly unpopular.