Storage Virtualization(1.5)

1、Storage Virtualization存储虚拟化存储虚拟化Agenda What is Storage Virtualization and why do End Users need it? SNIA Shared Storage Model Storage Virtualization Taxonomy A survey through various Virtualization approachesWhat is Storage Virtualization and why do End Users need it?What basic functionality do user

2、sneed from Storage?Storage Utilization (non-virtualized) Disk: 30 - 50% Tape: 20 - 40%Availability requirements Approaching 100% (e-business)99.999% Zero tolerance for downtime planned or unplannedMTTF客户面临的技术问题厂商C厂商B厂商A驱动驱动A驱动驱动A驱动驱动B驱动驱动B驱动驱动C远程镜像远程镜像 ?能否跨存储服务器实施能否跨存储服务器实施拷贝服务拷贝服务?需要有几套存储管理界需要有几套存储

3、管理界面面?扩充磁盘容量的时候是扩充磁盘容量的时候是否被迫购买拷贝服务的否被迫购买拷贝服务的license?没空间了没空间了没空间了没空间了没空间了空余空间010101010101010101010010101101001000数据迁移SAN管理控制台管理控制台A管理控制台管理控制台 C管理控制台管理控制台 B快照快照?磁盘的利用率高吗磁盘的利用率高吗?数据迁移造成的停机时数据迁移造成的停机时间是否很多间是否很多?The Management NightmareToo many different: Servers Operating systems Storage systems DAS,

4、NAS, SAN Interface: FC, SCSI, iSCSI, SAS, SATA,IB Storage Media: disk, tape, flash chip Management consolesIT staff skill levels and budget pressuresTraditional Architecture Storage is physical Connections Presentation Access and Configuration Results in: Complexity, Reboots, Downtime, $ Multiple ma

5、nagement systems - complex Inconsistent Incompatible Incomplete Result: ever-increasing storage management costs Cant support todays rapid data growthDefinitionSNIA : Storage virtualization is an abstraction of storage that separates the host view from the storage system implementation. 存储虚拟化最通俗的理解就

6、是对存储硬件资源进行抽象化表现(百百度度百科百科)What is Storage Virtualization? An abstraction of detail that separates layers Host implementation (Application, OS, HBA) Network implementation (Switch, Router, Gateway) Storage implementation (Array, Library, Device) Makes invisible to host: physical pathing device charact

7、eristics physical data location Provides location and implementation transparency Enables Dynamic Operations Enables transparent “on the fly” reconfiguration Allow data location to change transparently to host environmentBenefits of Virtualization Openness to new server, network and storage technolo

8、gy Significantly reduced downtime planned and unplanned Increased storage asset utilization Reduced storage capital cost Reduced management complexity (Potentially) Improved performance Load spreading, balancing, multi-pathing, heuristic shiftingBenefits of Virtualization Must-Have Architecture for

9、the future Increased Scalability, Security, Flexibility Managed file systems and volume managers Simplify definition of storage policies and procedures Improve delivery and quality of Storage ServicesA “virtual storage connection”SNIA Shared Storage ModelSNIA Storage Virtualization TaxonomyDisk (Dri

10、ve) Virtualization Has been common in disk drives for two decades Physical data layout Cylinders, heads, sectors Media defects Virtual data layout Linear array of numbered blocks “Defect-free” vs. “Flaw map” Implemented in Disk firmware Exported by ATA & SCSI ( FCP) command protocolsDisk (Drive)

11、 VirtualizationVirtualization Makes “Devices” from Devices Physical disks Fixed size Bounded performance Do break (occasionally) Virtual disks As big, small or as many as users need As fast as users & applications need As reliable as users & applications need Can grow(!), shrink or morphWher

12、e Does Virtualization Reside?HostNetworkStorageDeviceHost-based VirtualizationVirtualization in the network:(In-band with appliances)In-band vs Out-of-bandIBM SVCIBM SVCHDS HDS TagmaStoreTagmaStore华赛华赛 VISVISSANRAD SANRAD vStorvStorLSI SVMLSI SVMEMC EMC InvistaInvistaEvolution Of Virtualization Serv

13、ices Unified Management Virtualization plus Automation to deliver on SLAs Standardization (SNIA SMI-S) becomes very important T11 effort to create a Fabric API Intelligence Standard (FAIS) Automatic and Intelligent Storage Provisioning Automatic Data Migration Services Data Lifecycle Management Data

14、 center-wide Volumes and File SystemsIBM SAN Volume ControllerSANEMCSymmetrixSVCEMCCLARiiONHPEMA/MAIBMESSIBMFAStTHDSLightningHDSThunderVirtualDiskVirtualDiskServerVirtualDiskServerVirtualDiskContinuous Data ReplicationSVC原理SVCSVC将多个磁盘存储控制器管理起来，将存储控制器划分的多个将多个磁盘存储控制器管理起来，将存储控制器划分的多个LUNLUN（SVCSVC称为称为MD

15、isk）再次条带化，根据性能的高低划分成）再次条带化，根据性能的高低划分成不同的磁盘池不同的磁盘池MDiskGroup (MDG)，再从磁盘池中切割，再从磁盘池中切割VDiskVDisk分给应用服务器。对于应用服务器来说，它们可见的只是逻辑分给应用服务器。对于应用服务器来说，它们可见的只是逻辑磁盘，也就是磁盘，也就是VDisk，后端的物理磁盘对其是不可见的，后端的物理磁盘对其是不可见的SVC原理每个MDisk都会被划分为多个Extent，extend类似于RAID组中的条带化大小。每个Extent的最小值是16MB，最大值是2GB，该值的大小由MDG来定义。这些Extent按照每个MDisk从头到尾被顺序编号条带化映射Image映射顺序映射SVC 异构存储的灾备ServerServer