VNX Snapshot
Upon completion of this module, you should be able to:
• Describe VNX Snapshot operations
• Manage VNX Snapshot and Sessions
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
1
VNX Snapshot
Lesson 1: VNX Snapshots: Theory and Operation
During this lesson the following topics are covered:
• Purpose of VNX Snapshots
• VNX Snapshots requirements
• VNX Snapshots managed objects
• VNX Snapshots theory of operations
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
2
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
3
VNX Snapshots Requirements
Environment
System Requirements
Hardware
VNX Storage System
Two 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 32
VNX Snapshot enabler
Management Software
Unisphere UI
Navisphere Secure CLI
SnapCLI
Operating Systems
HP-UX
IBM AIX
Linux
Solaris
Windows Server
Refer to EMC Support Matrix for a complete
list
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
4
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
5
VNX Snapshots Characteristics
• Scalability
Primary
LUN
 256 snapshots per LUN
 Thin provisioned copies
 Lower write performance
2:00 pm
Snapshot
Dev
Snapshot
4:00 pm
Snapshot
Patch 1
Snapshot
6:00 pm
Snapshot
Patch 2
Snapshot
Copyright © 2014 EMC Corporation. All Rights Reserved.
impact
• Functionality
 Snapshot of a Snapshot
 RecoverPoint support
 Clone support
• Consistency Groups
VNX Snapshot
6
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
7
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
8
SnapView and VNX Snapshot Terminology
Comparison
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
9
Snapshot Technology Comparison: Source LUN
Writes
Copy on first write
Copyright © 2014 EMC Corporation. All Rights Reserved.
Redirect on write
VNX Snapshot
10
Snapshot Technology Comparison: Snapshot Reads
Read from two places
Copyright © 2014 EMC Corporation. All Rights Reserved.
Read from a single place
VNX Snapshot
11
VNX Snapshot Operations
• 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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
12
Create a VNX Snapshot
Primary LUN
Lun_20
Snap 1 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
Snap 1
Snap 2 (R/O)
Copyright © 2014 EMC Corporation. All Rights Reserved.
Snap 2
...
Creation time: 9pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
VNX Snapshot
13
Create a VNX Snapshot Mount Point (SMP)
Primary LUN
Lun_20
Snap 1 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
Snap 1
SMP1
Snap 2 (R/O)
Copyright © 2014 EMC Corporation. All Rights Reserved.
Snap 2
...
Creation time: 9pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
VNX Snapshot
14
Attach a VNX Snapshot to a SMP
Primary LUN
Lun_20
Snap 1 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
Snap 1
Snap 2 (R/W)
Copyright © 2014 EMC Corporation. All Rights Reserved.
Snap 2
SMP1
...
Creation time: 9pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN: SMP1
VNX Snapshot
15
Copy a VNX Snapshot (Snap of a Snap)
Primary LUN
...
Lun_20
Snap 1
Snap 2
Snap 3
Snap 1 (R/W)
Snap 2 (R/W)
Snap 2 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
Copyright © 2014 EMC Corporation. All Rights Reserved.
Creation time: 9pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN: SMP1
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
VNX Snapshot
16
Snap of a Snapshot Mount Point
...
Lun_20
Primary
LUN
Snap 1
Snap 1 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN:
LUN_20
Primary LUN:
LUN_20
Attached LUN:
Snap 2
Snap 2 (R/W)
Creation time: 9pm
Last modify time:
Last modified by:
Source LUN:
LUN_20
Primary LUN:
LUN_20
Attached LUN:
SMP1
SMP1
Snap 2.1
Snap 1 (R/O)
Creation time: 10pm
Last modify time:
Last modified by:
Source LUN: SMP1
Primary LUN:
LUN_20
Attached LUN:
Copyright © 2014 EMC Corporation. All Rights Reserved.
Snap 2.2
Snap 2 (R/O)
Creation time: 11pm
Last modify time:
Last modified by:
Source LUN: SMP1
Primary LUN:
LUN_20
Attached LUN:
SMP1
VNX Snapshot
17
Detach a VNX Snapshot to a SMP
Primary LUN
Lun_20
Snap 1 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
Snap 1
Snap 2 (R/W)
Copyright © 2014 EMC Corporation. All Rights Reserved.
Snap 2
X
SMP1
...
Creation time: 9pm
Last modify time: 11:47pm
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN: SMP1
VNX Snapshot
18
Destroy a VNX Snapshot
Primary LUN
Lun_20
Snap 1 (R/O)
Creation time: 8pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
Snap 1
X
Snap 2 (R/O)
Copyright © 2014 EMC Corporation. All Rights Reserved.
Snap 2
...
Creation time: 9pm
Last modify time:
Last modified by:
Source LUN: LUN_20
Primary LUN: LUN_20
Attached LUN:
SMP1
VNX Snapshot
19
Attach a Consistency Snapshot
Host 1
Host 2
Lun_20
SMP
LUN_20
Lun_21
SMP
LUN_21
R/W
CG1
Copyright © 2014 EMC Corporation. All Rights Reserved.
CG
Snap 1
VNX Snapshot
20
VNX Snapshot
Lesson 1: Summary
During this lesson the following topics were covered:
• Purpose of VNX Snapshots
• VNX Snapshots requirements
• VNX Snapshots managed objects
• VNX Snapshots theory of operations
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
21
VNX Snapshot
Lesson 2: Managing VNX Snapshots
During this lesson the following topics are covered:
• Displaying VNX Snapshots
• VNX Snapshot expiration
• Cascading VNX Snapshots
• Restoring VNX Snapshots
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
22
VNX Snapshot Management
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshots
23
VNX Snapshot Properties
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
24
VNX Snapshot Consistency Group Properties
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
25
Storage Pool Properties - VNX Snapshots
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
26
VNX Snapshot and SMP Creation
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
27
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
28
Cascading VNX Snapshots
• VNX Snapshot of an attached Snapshot Mount Point
Not attached
Copyright © 2014 EMC Corporation. All Rights Reserved.
Attached
SnapView Snapshots
29
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
30
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
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
31
Restoring a Primary LUN
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
32
VNX Snapshot Configuration Wizard
Copyright © 2014 EMC Corporation. All Rights Reserved.
SnapView Snapshots
33
VNX Snapshot
Lesson 2: Summary
During this lesson the following topics were covered:
• VNX Snapshot Management
• VNX Snapshot properties
• VNX Snapshot expiration and restore
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
34
VNX Snapshot Summary
Key points covered in this module:
• VNX Snapshot provides a point-in-time virtual copy of poolbased 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
Copyright © 2014 EMC Corporation. All Rights Reserved.
VNX Snapshot
35