存储数据保护Raid技术DDP说明.pptx

1、,存储高级数据保护技术-DDP说明,1,Volumes,SANtricity RAID Protection,Volume groupsRAID 0,1,10,5,6Intermix RAID levelsVarious group sizesDynamic disk poolsMin 11 SSDsMax 120 SSDsUp to 10 disk pools per system,2,NetApp Confidential,Volume Groups,Volumes,Host LUNs,SSDs,Disk Pool,SSDs,Host LUNs,SANtricity RAID Levels

2、,RAID 0 stripedRAID 5 data disks and rotating parity,RAID 1(10)mirrored and stripedRAID 6(P+Q)data disks and rotating dual parity,3,NetApp Confidential,Block-level striping with a distributed parity,Traditional RAID Volumes,Disk drives organized into RAID groupsVolumes reside across the drives in a

3、RAID groupPerformance is dictated by the number of spindlesHot spares sit idle until a drive failsSpare capacity is“stranded”,24-drive system with 2 10-drive groups(8+2)and 4 hot spares,4,Traditional RAIDDrive Failure,Data is reconstructed onto hot spareSingle drive responsible for all writes(bottle

4、neck)Reconstruction happens linearly(one stripe at a time)All volumes in that group are significantly impacted,24-drive system with 2 10-drive groups(8+2)and 4 hot spares,5,The Problem,The Large-Disk-Drive ChallengeStaggering amounts of data to store,protect,accessSome sites have thousands of large-

5、capacity drivesDrive failures are continual,particularly with NL-SAS drivesProduction I/O is impacted during rebuildsUp to 40%in many casesAs drive capacities continue to grow,traditional RAID protection is pushed to its limitDrive transfer rates have not kept up with capacitiesLarger drives equal l

6、onger rebuildsanywhere from 10+hours to several days,6,4TB+,Dynamic Disk Pools,Maintain SLAs during drive failureStay in the greenPerformance drop is minimized following drive failureDynamic rebalance completes up to 8x faster than traditional RAID in random environments and up to 2x faster in seque

7、ntial environmentsLarge pool of spindles for every volume reduces hot spotsEach volume spread across all drives in poolDynamic distribution/redistribution is a nondisruptive background operation,7,Balanced:Algorithm randomly spreads data across all drives,balancing workload and rebuilding if necessa

8、ry.,Easy:No RAID or idle spares to manage active spare capacity on all drives.,Combining effort:All drives in the pool sustain the workloadperfect for virtual mixed workloads or fast reconstruction if needed.,Flexible:Add ANY*number of drives for additional capacitysystem automatically rebalances da

9、ta for optimal performance.,Traditional RAID Technology,Innovative Dynamic Disk Pools,8,“With Dynamic Disk Pools,you can add or lose disk drives without impact,reconfiguration,or headaches.”,*After the minimum of 11.,9,Data Rebalancing in Minutes vs.Days,Hours,2.5 Days,1.3 Days,Typical rebalancing i

10、mprovements are based on a 24-disk mixed workload,More than 4 Days,Business Impact,99%ExposureImprovement,Maintain business SLAs with a drive failure,RAID Level Comparison,10,NetApp Confidential,Dynamic Disk Pools Overview,DDP dynamically distributes data,spare capacity,and parity information across

11、 a pool of SSDsAll drives are active(no idle hot spares)Spare capacity is available to all volumesData is dynamically recreated/redistributed whenever pools grows or shrinks,11,NetApp Confidential,DDP:Simplicity,Performance,Protection,Simplified administrationNo RAID sets or hot spares to manageData

12、 is automatically balanced within poolFlexible disk pool sizing optimizes capacity utilizationConsistent performance Data is distributed throughput the pool(no hot spots)Performance drop is minimized during a drive rebuildSignificantly faster return to optimal stateRelentless data protectionSignific

13、antly faster rebuild times as data is reconstructed throughout the disk poolPrioritized reconstruction minimizes exposure,12,NetApp Confidential,DDP Insight:How It Works,Each DDP volume is composed of some number of 4GB“virtual stripes”called dynamic stripesEach D-stripe resides on a pseudo-randomly

14、 selected set of 10 drives from within the poolD-stripes are allocated at time of volume creation and allocated sequentially on a per-volume basis,13,NetApp Confidential,24-SSD pool,DDP SSD Failure,For each D-Stripe which has data on failed SSD:Segments on other SSDs are read to recreate dataA new S

15、SD is chosen to write segments from failed SSDRebuild operations run in parallel across all SSDs,14,NetApp Confidential,DDP Multiple Disk Failure,If two SSDs have failed system will rebuild critical segments firstBrown and Light Blue,15,NetApp Confidential,If additional SSDs fail new critical segmen

16、ts will be identified and rebuiltBlue,Orange and Pink,DDP Adding SSDs To Pool,Add a single SSD or add multiple SSDs simultaneouslyImmediately rebalances data to maintain equilibriumSegments are just moved(does not reconstruct RAID),16,NetApp Confidential,23-SSD pool,Dynamic Stripe:A Closer Look,Data is written within a D-stripe using RAID 6Each RAID 6 stripe is 1MB(8+2 with 128K segment size)Each D-stripe has 4,096 traditional RAID 6 stripesA D-piece is one drives worth of D-stripe data,17,NetAp