SNIA-SDC23-Helmick-Host-Workloads-Achieving-WAF_0.pdf

1、1|2023 SNIA.All Rights Reserved.Virtual ConferenceSeptember 28-29,2021Host Workloads Achieving WAF=1 in an FDP SSDPresented by Dan Helmick,PhD2|2023 SNIA.All Rights Reserved.AgendaBackground FDP Overview Visualizing Writes in an SSD QD1 impacts with FDPSome example WAF=1 workloads Circular FIFO Modi

2、fied Circular Buffer Log Structured File Systems Probabilistic Log Structured File Systems with Mismatched Host Extent and SSD RU3|2023 SNIA.All Rights Reserved.Flexible Data Placement(FDP)Overview Apps can direct write data to be co-located in an SSD Possible for a VMM to set-up defaults for legacy

3、 VMs Filling and deallocating appropriately can achieve WAF=12023 Flash Memory Summit.All Rights Reserved3Logical ViewSSDApp 1App 2App 3StreamsFlexible Data Placement(FDP)Zoned Namespaces(ZNS)Open Loop WAF=1Polling for WAF=1WAF=1 or ErrorBackwards CompatibleBackwards CompatibleNot Backwards Compatib

4、leStreams Granularity Size(SGS)Reclaim Unit(RU)SizeZone Capacity 1 allowedQD1 allowedQD1 requires Zone AppendFull FTL mapping requiredFull FTL mapping requiredPotential for compacted FTL Mapping4|2023 SNIA.All Rights Reserved.Simplified SSD Composition Reclaim Units(RUs)are composed of 1 or more Era

5、se Blocks(EBs)Ex:RU is equal to a SuperBlock(SB)SB=1 EB per Plane for every Die RU is filled in order even if the LBAs are out-of-order After filling an RU,a new set of empty EBs are selected to create a new RU Rules may be applied in selecting EBs from the Free Pool Ex:1 EB per Plane for every Die

6、to create a SB Diagramming a Conventional Drive =1 RUH Random trafficEBEBEBRUWrites fill the RUFree Pool of EBsFilled RUs/SBs with InvalidsRU/SB being FilledFree Pool(OP)Incoming Writes(Append Point)Decreasing Valid CountMost Simplified Drive ViewNot diagrammed:GC moves valid data and adds to Free P