Zoned storage devices, such as flash drives and shingled magnetic disks, are divided into units called zones, in which all writes must be sequential. We develop techniques to improve I/O performance on these devices.
Shingled Magnetic Recording (SMR) drives offer higher data density at the cost of disallowing random writes. This higher density comes at a prices: all writes within large zones must be sequential. We are developing file system and storage stack architectures that best support this sequential only writes requirement.
Shingled Magnetic Recording (SMR) drives offer higher data density at the cost of disallowing random writes. This sequential writes only restriction aligns well with log-structured filesystem (LFS); LFS always writes sequentially avoiding read-modify-updates. However, this no-overwrite structure generates invalid (dirty) data, which ultimately needs to be garbage-collected (typically called cleaning in the context of LFS). Historically, cleaning disrupts application IO leading to high tail latencies. We investigate the methods that can reduce this latency spike.
People: Surbhi Palande
Systopia lab is supported by a number of government and industrial sources, including Cisco Systems, the Communications Security Establishment Canada, Intel Research, the National Sciences and Engineering Research Council of Canada (NSERC), Network Appliance, Office of the Privacy Commissioner of Canada, and the National Science Foundation (NSF).