SMR HDD Data-Preserving Depop
Abstract
Hard Disk Drive (HDD) Data-Preserving Depop (DPD) allows a drive with a failed read/write head or recording surface to continue operating at reduced capacity by disabling the affected surface rather than failing the entire device. Although this capability can preserve a large fraction of the drive’s usable media, today’s local and distributed filesystems generally assume that head or surface failures manifest as critical device errors, often triggering whole-disk replacement and full data reconstruction. In this work, we adapt the xfs-zoned filesystem for SMR drives to handle depopulation-related failures and isolate the logical regions corresponding to failed surfaces from future allocation, allowing the remaining regions of the drive to continue serving data. We study how depop-aware local recovery interacts with distributed storage, using HDFS as a representative system. Our results show that a DPD-enabled SMR-based system reduces recovery time by approximately 19× compared with conventional whole-drive recovery.
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