SnapView Clones Upon completion of this module, you should be able to: • Describe SnapView Clone operations • Manage SnapView Clones Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 1 SnapView Clones Lesson 1: SnapView Clone: Theory and Operation During this lesson the following topics are covered: • Purpose of SnapView Clones • SnapView Clones requirements • SnapView Clones managed objects • SnapView Clones theory of operations Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 2 SnapView Clones • SnapView Clone – a full copy of a LUN internal to a storage • system Population latency Clones take time to populate (synchronize) Data in the LUN must be duplicated • Protected No changes will be made to the clone UNLESS the user writes to it • 2-way synchronization Clones may be incrementally updated from the source LUN Source LUNs may be incrementally updated from a clone • Copies real data Clone must be EXACTLY the same size as Source LUN Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 3 SnapView Clones Operations • Create Clone Group Changes LUN to source LUN • Add clone to Clone Group Changes LUN to clone • Synchronize Clone Data copied from source LUN to clone • Fracture clone (may be a consistent operation) Stops updating of clone with new source LUN data • Remove clone Clone becomes an independent LUN Cannot be synchronizing or reverse synchronizing • Destroy Clone Group Source LUN becomes an independent LUN Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 4 Clone Initial Synchronization • Copy contents of source LUN to clone Overwrites clone with source LUN data Host access allowed to source LUN at all times No host access to clone while not fractured Production Host Source LUN Backup Host X Clone 1 Copyright © 2014 EMC Corporation. All Rights Reserved. Clone 2 ... Clone 8 VNX Snapview Clones 5 Clone Private LUN (CPL) and Fracture Log • Fracture Log Bitmap stored in SP memory Tracks modified extents between source LUN and each clone Allows incremental resynchronization – in either direction Determines extent size 1 block for each GB of source LUN size, with a minimum of 128 KB Example: 512 GB clone. Extent size = 512 blocks = 256 KB • Private LUN for each SP Must be 1 GB or greater Used for all clones owned by the SP No clone operations allowed until CPL created Contains persistent Fracture Logs Classic LUNS only Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 6 Clone Reverse Synchronization • Restore source LUN with contents of clone Overwrites source LUN with clone data Host access allowed to source LUN No host access to clone Source LUN instantly appears to contain clone data Production Host Source LUN X Backup Host X X Clone 1 Copyright © 2014 EMC Corporation. All Rights Reserved. Clone 2 ... Clone 8 VNX Snapview Clones 7 Reverse Synchronization and Protected Restore • Non-Protected Restore Host → source LUN writes mirrored to clone When Reverse Synchronization completes: Reverse-synchronized clone remains unfractured Other clones remain fractured • Protected Restore Host → source LUN writes not mirrored to clone When Reverse Synchronization completes: All clones are fractured Protects against source LUN corruption Configure at the individual clone level Must be globally enabled first with ‘Allow Protected Restore” checkbox Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 8 Trespassing Source LUNs and Clones • Source LUN Trespass Peer SP acquires clones Peer SP acquires Fracture Logs (through CPL) Peer SP resumes any synchronization operations • Clone Trespass User or host can initiate trespass of a fractured clone Desirable for load balancing across SPs Fractured clone need not be on same SP as source LUN Synchronization trespasses clone as necessary Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 9 SnapView Clones Lesson 1: Summary During this lesson the following topics were covered: • Purpose of SnapView Clones • SnapView Clones requirements • SnapView Clones managed objects • SnapView Clones theory of operations Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 10 SnapView Clones Lesson 2: Clone Configuration During this lesson the following topics are covered: • Clone configuration • Creating and populating Clone Groups Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 11 Configuring the Clone Private LUNs Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 12 Creating a Clone Group Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 13 Adding a Clone to a Clone Group Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 14 Clone Group Properties Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 15 Clone Operations Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 16 Clone Operations - Consistent Fracture Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 17 Clone Time of Fracture • Allows the user to know the date/time when the Clones images • • • • were administratively fractured Clones will stamp the time ONLY when the clones were administrative fractured by the user and the images were a point in time copy (consistent state) The time will be stored persistently inside the current clones private area in PSM All Clones involved in a Consistent Fracture operation reports the same time of fracture Private LUN for each SP Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 18 Clone Configuration Wizard Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 19 SnapView Clones Lesson 2: Summary During this lesson the following topics were covered: • Clone Private LUN configuration • Clone operations Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 20 Summary Key points covered in this module: • SnapView Clone is a full copy of a LUN internal to a VNX storage system • Clones take time to duplicate data from source • Clones must be exactly the same size Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 21 This slide is intentionally left blank. Copyright © 2014 EMC Corporation. All Rights Reserved. VNX Snapview Clones 22