copyright © 2014 emc corporation. all rights reserved. vnx snapshot upon completion of this module,...
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Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
Upon completion of this module, you should be able to:• Describe VNX Snapshot operations• Manage VNX Snapshot and Sessions
VNX Snapshot 1
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VNX Snapshot
During this lesson the following topics are covered: • Purpose of VNX Snapshots• VNX Snapshots requirements• VNX Snapshots managed objects• VNX Snapshots theory of operations
Lesson 1: VNX Snapshots: Theory and Operation
VNX Snapshot 2
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VNX Snapshots
• VNX Snapshots – virtual point-in-time copy of a LUN Allows to create snapshots of pool-based LUNs Use pointer-based replication and Relocate on First Write (ROW)
technology Make use of the source LUN’s parent Pool to store original data Have three managed objects: Snapshot, Snapshot Mount Point,
Consistency Group
• VNX Snapshots are managed by Unisphere Navisphere Secure CLI SnapCLI
VNX Snapshot 3
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VNX Snapshots Requirements Environment System Requirements
Hardware VNX Storage SystemTwo or more Servers (if the VNX Snapshots snap is to be accessed by a host), each attached to the VNX that will run VNX Snapshots
Storage System Software VNX Operating Environment for Block Release 32VNX Snapshot enabler
Management Software Unisphere UINavisphere Secure CLISnapCLI
Operating Systems HP-UXIBM AIXLinuxSolarisWindows Server
Refer to EMC Support Matrix for a complete list
VNX Snapshot 4
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VNX Snapshots Managed Objects
• Primary LUN Pool LUN from which the snapshot is taken
• Snapshot Point-in-time copy of a LUN
• Snapshot Mount Point An object that is exposed to the host through a storage group
• Consistency Group Persistent grouping of primary LUNs or Mount Points
VNX Snapshot 5
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• Scalability 256 snapshots per LUN Thin provisioned copies Lower write performance
impact
• Functionality Snapshot of a Snapshot RecoverPoint support Clone support
• Consistency Groups
VNX Snapshots Characteristics
VNX Snapshot 6
Primary LUN
2:00 pm Snapshot
4:00 pm Snapshot
6:00 pm Snapshot
Dev Snapshot
Patch 1 Snapshot
Patch 2 Snapshot
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VNX Snapshot Mount Points
• A Snapshot Mount Point is a container that holds SCSI attributes Behaves like a LUN of the same size as the Primary LUN Added as a member LUN in the secondary host Storage Group
• A VNX Snapshot is attached to a Snapshot Mount Point (SMP) in order to allow host access to the replica data
• VNX Snapshots are easily switched on one SMP No SCSI rescan is required on the host
• Must have an attached Snapshot for data to be host-visible
VNX Snapshot 7
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VNX Snapshot Consistency Group
• A group of Primary LUNs or VNX Snapshot Mount Points• Snapshots can be made of the entire Group• Primary LUNs or VNX SMPs can be added to the Group
Snapshots may have more or fewer members as a result Snapshots being restored must have the same members as the
Group
• Does not require application I/O to be stopped• Related terms
VNX Snapshot Set - a Snapshot of a Consistency Group VNX Snapshot Family – a group of Snapshots of the same LUN
VNX Snapshot 8
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VNX Snapshot Term SnapView Term Definition
Snapshot Session Point in time copy
Restore Rollback Restore primary LUN to point in time copy
Attach Activate Make the point in time copy accessible to a host
Detach Deactivate Remove the point in time copy from the host
Consistency Group n/a Persistent grouping of primary LUNs or Mount Points
Snapshot Family n/a Pool LUN, all of its associated mount points and all of their snapshots
Primary LUN Source LUN Pool LUN that can be used by VNX Snapshots
Snapshot Mount Point Snapshot [LUN] LUN that host uses to access the snapshot data
SnapView and VNX Snapshot Terminology Comparison
VNX Snapshot 9
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Snapshot Technology Comparison: Source LUN Writes
VNX Snapshot 10
Redirect on writeCopy on first write
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Snapshot Technology Comparison: Snapshot Reads
VNX Snapshot 11
Read from a single placeRead from two places
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VNX Snapshot Operations
VNX Snapshot 12
• Create a Snapshot• Create a Snapshot Mount Point (SMP)• Attach a Snapshot• Copy a Snapshot• Snap a Snapshot Mount Point (Cascading Snapshots)• Detach a Snapshot Mount Point• Destroy a Snapshot• Attach a Consistency Snapshot
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Create a VNX Snapshot
VNX Snapshot 13
Primary LUN
Snap 1 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Snap 2 (R/O)
Creation time: 9pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Lun_20
Snap 1
Snap 2
. . .
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Create a VNX Snapshot Mount Point (SMP)
VNX Snapshot 14
Primary LUN
Snap 1 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Snap 2 (R/O)
Creation time: 9pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Lun_20
Snap 2
. . .
Snap 1 SMP1
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Attach a VNX Snapshot to a SMP
VNX Snapshot 15
Primary LUN
Snap 1 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
. . .
Snap 1
Lun_20
Snap 2
Snap 2 (R/W)
Creation time: 9pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN: SMP1
SMP1
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Copy a VNX Snapshot (Snap of a Snap)
VNX Snapshot 16
Primary LUN
Snap 1 (R/W)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Snap 2 (R/W)
Creation time: 9pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN: SMP1
. . .
Snap 2 Snap 3
Snap 2 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Lun_20
Snap 1
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Snap of a Snapshot Mount Point
VNX Snapshot 17
PrimaryLUN
Snap 1 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Snap 2 (R/W)
Creation time: 9pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN: SMP1
. . .Lun_20
Snap 1
Snap 2.2Snap 2.1
Snap 1 (R/O)
Creation time: 10pmLast modify time: Last modified by:Source LUN: SMP1Primary LUN: LUN_20Attached LUN:
Snap 2 (R/O)
Creation time: 11pmLast modify time: Last modified by:Source LUN: SMP1Primary LUN: LUN_20Attached LUN: SMP1
Snap 2
SMP1
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Detach a VNX Snapshot to a SMP
VNX Snapshot 18
Primary LUN
Snap 1 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
. . .
Snap 1
Lun_20
Snap 2
Snap 2 (R/W)
Creation time: 9pmLast modify time: 11:47pmLast modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN: SMP1
SMP1X
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Destroy a VNX Snapshot
VNX Snapshot 19
Primary LUN
Snap 1 (R/O)
Creation time: 8pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Snap 2 (R/O)
Creation time: 9pmLast modify time: Last modified by:Source LUN: LUN_20Primary LUN: LUN_20Attached LUN:
Lun_20
Snap 2
. . .
Snap 1 SMP1
X
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Attach a Consistency Snapshot
VNX Snapshot 20
CG1CG
Snap 1
R/W
Lun_21
Lun_20
SMPLUN_20
SMPLUN_21
Host 1 Host 2
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VNX Snapshot
During this lesson the following topics were covered:• Purpose of VNX Snapshots• VNX Snapshots requirements• VNX Snapshots managed objects• VNX Snapshots theory of operations
Lesson 1: Summary
VNX Snapshot 21
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VNX Snapshot
During this lesson the following topics are covered: • Displaying VNX Snapshots• VNX Snapshot expiration• Cascading VNX Snapshots• Restoring VNX Snapshots
Lesson 2: Managing VNX Snapshots
VNX Snapshot 22
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VNX Snapshot Properties
SnapView Snapshots 24
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VNX Snapshot Consistency Group Properties
SnapView Snapshots 25
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Storage Pool Properties - VNX Snapshots
SnapView Snapshots 26
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VNX Snapshot and SMP Creation
SnapView Snapshots 27
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VNX Snapshot Expiration
• Every VNX Snapshot may have an optional expiration date
• Expired VNX Snapshots are destroyed at regular intervals VNX array scans for expired
snapshots once an hour
• Set an expiration date only after Auto-Delete is disabled
• User is warned before Snapshots are deleted
SnapView Snapshots 28
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Cascading VNX Snapshots
• VNX Snapshot of an attached Snapshot Mount Point
SnapView Snapshots 29
Not attached
Attached
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Restore
• Use VNX Snapshot to restore a primary LUN or a SMP• Data in the LUN is changed to match the data in the snapshot
Does not change the “Restore Point” snapshot Return no the poin-in-time of the source data
• Used when recovering from data corruption• LUN with state ‘Initializing’ while being restored
Changes back to ‘Ready’ after the restore is complete
• Restoring can change the LUN size If the source snapshot was taken before the primary LUN expansion
or shrinking
SnapView Snapshots 30
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Restore Considerations
• Restore with SnapView Snapshots and VNX Snapshots Restore a primary LUN from a VNX Snapshot
All SnapView session must be manually stopped Restore a primary LUN from a SnapView Snapshot
VNX Snapshots are unaffected
• Stop application access to the primary LUN• Flush the buffers for the drive
SnapView Snapshots 31
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Restoring a Primary LUN
SnapView Snapshots 32
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VNX Snapshot Configuration Wizard
SnapView Snapshots 33
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VNX Snapshot
During this lesson the following topics were covered:• VNX Snapshot Management• VNX Snapshot properties• VNX Snapshot expiration and restore
Lesson 2: Summary
VNX Snapshot 34
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VNX Snapshot Summary
Key points covered in this module:• VNX Snapshot provides a point-in-time virtual copy of pool-
based LUNs using ROW technology• A Snapshot Mount Point is a container that holds SCSI attributes,
behaves like a LUN, and is added to host Storage Group
VNX Snapshot 35