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  • Storage consolidation increases storage utilization, maintenance,
  • Block aggregation Space mgt thru combining, slicing native storage into new aggregated block storage Strip the aggregated block across several native devices redundancy through local and remote mirroring and point-in-time copy
  • Clients with different OS Each client has STClient installed into VFS (Unix) and as IFS on Windows Other computers which are STServer which runs ST Server code. Manages file system meta-data (File attributes, security info, location, locks etc) ST Servers can be clustered for scalability and availability of meta-data operations Admin client can perform administrative activities without interrupting applications on clients Data directly transfers from Storage to client thru high bandwidth SAN – eliminating the bottleneck Control Network IP Network, carries lock state and metadata => load is minimal. Client’s normal comm is not effected SAN High Bandwidth, direct transfer ST is designed such that it is independent of SAN Fabric – Fiber Channel, SCSI
  • These protocols makes it look like local file system Locks enable the file sharing between clients

SS.ppt SS.ppt Presentation Transcript

    • IBM Storage Tank Architecture
    • Shirish Tatikonda
  • Storage Systems - Evolution
    • Directly Attached Storage (DAS)
      • Hard Disk Drive (HDD)
      • Redundant Array of Inexpensive Disks (RAID)
    • Network Attached Storage (NAS)
      • NFS, CIFS (Common Internet File System)
    • Storage Area Network (SAN)
      • Over FC channel, iSCSI, ATA etc.
    • SAN + NAS
      • IBM Storage Tank, GFS (Linux), WinFS (Longhorn)
  • Directly Attached Storage (DAS)
    • Data + Control through internal I/O busses
    • Not Scalable
    • Data sharing is limited
  • Network Attached Storage (NAS)
    • Data + Control through underlying (TCP/IP) network
    • Easy File Sharing
    • Network congestion for large data transfers
  • Storage Area Network
    • Data + Control over SAN
    • A SAN is a specialized, high-speed network attaching servers and storage devices
    • Allows “any-to-any” connections
    • Data traffic is similar to traffic in local storage systems
      • Block Storage (~ SCSI)
      • File Storage (~ SMB, NFS)
    • LAN-Free, Server-Free SANs
  • LAN-Free Model Server-Free Model
  • Advantages of SANs
    • Flexible and scalable
    • High availability
    • Easy backup and restore
    • Easy disaster recovery
    • Storage and server consolidation
      • Easy maintenance
      • Easy commission or decommission of devices
    • Allows zoning subset of computers and storage systems
      • Security
      • Better space utilization
    • Allows virtualization
      • Heterogeneous physical devices
  • Storage Virtualization
    • Introduces a layer between computers and storage
    • Masks the physical layout of storage and gives a unified and logical pool of shared region
    • Storage is no longer controlled by individual servers
    • Block-level virtualization
    • File-level virtualization
  • Storage Virtualization Models
  • Goals of Storage Tank
    • Exploitation of SAN technology
    • Heterogeneous (multiplatform) data sharing
    • Policy-based storage and data management
    • Massive scalability of data, servers, and clients
    • High availability of servers and data
    • Global namespace and single-system semantics
    • Full and transparent data sharing across multiple platforms
    • High performance file I/O for all kind of files
  • Architecture
  • IBM Storage Tank Protocol
    • Comm. between servers and clients over IP network
    • Provides locking and ( strong ) consistency protocols
    • Opening a file
      • Client requests IFS to open the file
      • IFS contacts server to obtain metadata and lock
      • IFS accesses the data directly from device
    • Semi-preemptible locks
  • Storage Tank Client (1)
    • FSI and OS services are platform specific
    • CSM is platform independent (client end of ST and lease protocol)
    • STClient makes the ST file system transparent to applications
  • Storage Tank Client (2)
    • Caching at clients
      • To achieve low-latency access to meta-data and data
      • In memory cache
      • Caches data , meta-data , and locks
    • Lease Protocol for fail-over processing
      • Client failure
      • Server failure (flush the cache)
  • Semi-Preemptible locks
    • For exploiting the temporal locality
    • Similar to caching the data in distributed file system
      • Cached locks are retained even there are no open instances of the file
      • Server demands the client when needed
    • Reduces the communication between server and client
    • Such locks can be shared across multiple clients at the same time
    • Downgrading the exclusive locks
  • Storage Tank Server (1)
    • Portable, user-level application
    • One server or cluster of servers
      • All servers in cluster share the meta-data (through SAN)
    • Provides
      • Meta-data services
      • Administrative services
      • Storage management services
      • Data management services
    • Unlike NAS servers, these servers perform no data operations
    • Transaction mgt, memory mgt, and recovery
    • Implements clustering protocol (failover processing)
  • Storage Tank Server (2)
    • Meta-data services
      • Perform meta-data updates
      • Serve file system meta-data to clients
      • Grant file and data locks
      • Detect client failures and perform recovery (lease protocol)
    • Administrative services
      • Maintenance of server clusters, storage pools (based on QoS)
      • Commission and decommissions of server nodes
      • Manage physical storage devices
      • Taking snapshots of meta-data
  • Storage Tank Server (3)
    • Storage management services
      • Storage pool monitoring
      • Volume decommission
    • Data management services
      • Select service class for each file
      • Policy based file placement and backup
      • Moving data between storages
      • Taking snapshots of data and associated meta-data
    • ( service class: file allocation, caching options, availability requirements etc.)
  • SAN File System
    • Multiplatform, robust, scalable, and highly available file system
    • Storage mgt. solution that works with SAN
    • Provides a global namespace
    • Fileset
      • A portion of tree-structured global namespace
      • Each fileset is attached to a directory
      • Allow the metadata workload to be split between MDS in the cluster
    • Client sees fileset as a directory in which files can be created
    • Only administrator can create filesets
    • Storage pools
      • System pool
      • User pool
  • Policy based storage and data mgt.
    • Provide QoS parameters for creation of files etc.
  • In a Nutshell …
    • Exploitation of SAN technology
    • Support for heterogeneous clients
    • Support for multiple server platforms
    • Data sharing through a global uniform namespace
    • Highly-scalable storage pools and server clusters
    • High availability of data and system
    • Storage virtualization
    • Reduced administration costs