Hewlett Packard Enterprise HPE XP7 User manual

HPE XP7 Fast Snap User Guide
Part Number: 858749-403
Published: January 2019
Edition: 18
Abstract
This guide provides information about how to configure and use Fast Snap to store snapshots
in an XP7 Storage system. This document is intended for system administrators and Hewlett
Packard Enterprise representatives and authorized service providers who install, configure,
and operate the XP7 Storage system.

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Contents
Overview of Fast Snap............................................................................8
About Fast Snap........................................................................................................................... 8
Workflow for storing Fast Snap snapshot data...................................................................8
Components of Fast Snap............................................................................................................ 9
Fast Snap pairs................................................................................................................ 11
Volume components.........................................................................................................12
Snapshot tree components ............................................................................................. 13
Maximum number of Fast Snap pairs.............................................................................. 13
Consistency and snapshot groups................................................................................... 13
Snapshot Clones .............................................................................................................14
Snapshot trees and cascaded pairs ................................................................................14
Creating cascaded pairs.................................................................................................. 15
Volume differences between Fast Snap and Business Copy...........................................17
XP7 Storage software applications for Fast Snap............................................................20
How Fast Snap works................................................................................................................. 21
How Fast Snap uses pools and pool volumes................................................................. 21
Usage level rebalancing among parity groups................................................................. 21
How Fast Snap uses V-VOLs...........................................................................................22
How Fast Snap pairs are created.....................................................................................22
Using snapshot pairs (not cascaded) ..............................................................................23
Using cascaded pairs.......................................................................................................23
Workflow for creating groups and storing snapshot data using RAID Manager...............26
Methods of storing snapshot data.................................................................................... 28
Fast Snap pair restoration................................................................................................29
How Fast Snap pair status changes........................................................................................... 29
Fast Snap host access and pair status............................................................................ 31
Workflow for Fast Snap pair status changes....................................................................31
Copy threshold option and host server I/O performance for Fast Snap......................................33
Sharing Fast Snap volumes with other software applications.....................................................33
Sharing Fast Snap volumes that have Data Retention access attributes........................ 35
Sharing Fast Snap volumes with Auto LUN..................................................................... 38
Sharing Fast Snap volumes with Business Copy.............................................................38
Sharing Fast Snap volumes with Continuous Access Synchronous and Continuous
Access Journal.................................................................................................................41
Sharing Fast Snap volumes with High Availability........................................................... 44
Sharing Fast Snap volumes with Thin Provisioning and Thin Provisioning MF in a
single storage system.......................................................................................................53
Sharing Fast Snap volumes with Resource Partition....................................................... 54
Acronyms and abbreviations for XP7 Storage system software applications used in this
guide........................................................................................................................................... 54
Fast Snap system and planning requirements.................................. 55
Fast Snap system requirements................................................................................................. 55
Fast Snap licensed capacity requirements...................................................................... 55
Fast Snap shared memory requirements.........................................................................56
Fast Snap volume requirements...................................................................................... 56
Fast Snap data pool requirements................................................................................... 60
Fast Snap consistency group requirements.....................................................................61
Fast Snap snapshot group requirements......................................................................... 63
Contents 3

Fast Snap planning requirements............................................................................................... 63
Calculating the number of Fast Snap pairs based on pair tables.....................................64
Calculating Fast Snap pairs based on the snapshot estimated manageable capacity.... 64
Calculating Fast Snap pairs based on cache management devices................................65
Calculating the number of cache management devices.................................................. 66
Calculating the Fast Snap pair capacity for THP pools....................................................66
Fast Snap cache management device requirements.......................................................68
Calculating and assigning pool capacity.......................................................................... 69
External Storage and external volumes used as pool-VOLs............................................71
Simultaneous processing of multiple Fast Snap pair tasks..............................................71
Pair operations when pairs are cascaded ....................................................................... 72
Pair operations when pairs are not cascaded.................................................................. 83
Pair operations when a P-VOL is shared by multiple S-VOLs......................................... 84
Data recovery and backup differences between Fast Snap and Business Copy.............85
Removing Fast Snap.................................................................................................................. 86
Configuring Fast Snap..........................................................................88
Prerequisites for configuring Fast Snap......................................................................................88
Workflow for configuring Fast Snap............................................................................................ 88
Workflow for creating and managing Fast Snap pairs......................................................89
Creating Fast Snap data pools.........................................................................................89
Selecting pool volumes.................................................................................................... 92
Pool creation and data drive type priority.........................................................................94
Workflow for registering virtual volumes..................................................................................... 95
Editing the SSID for virtual volumes ................................................................................95
Changing V-VOL settings.................................................................................................98
Creating V-VOLs for Fast Snap S-VOLs........................................................................ 100
Overview of using RAID Manager to run commands through in-band connections................. 108
Changing system options that affect Fast Snap performance.................................................. 108
Managing Fast Snap Pairs..................................................................112
Fast Snap pair tasks..................................................................................................................112
Checking Fast Snap pair status................................................................................................ 112
Reloading Fast Snap configuration information........................................................................ 112
Workflow for creating and managing Fast Snap pairs...............................................................113
Workflow for creating Fast Snap pairs using Remote Web Console.........................................113
Creating Fast Snap pairs using Remote Web Console.............................................................114
Selecting a pool as your primary volume........................................................................117
Example of creating complex Fast Snap pairs..........................................................................118
Pair operations for each consistency group.............................................................................. 119
Adding Fast Snap pairs to snapshot or consistency groups using RAID Manager........ 119
Workflow for defining Fast Snap pairs and defining them in snapshot or consistency
groups using Remote Web Console...............................................................................119
Storing snapshot data or cloning pairs........................................................................... 119
Splitting Fast Snap pairs to store snapshot data...................................................................... 120
Splitting Fast Snap pairs to store snapshot data using RAID Manager......................... 121
Workflow for storing snapshot data or clone pairs in consistency groups.................................121
Using consistency group pair-split with shared volumes................................................122
Restoring Fast Snap pairs........................................................................................................ 124
Failure during Fast Snap pair restore.............................................................................126
Restoring suspended Fast Snap pairs........................................................................... 126
Fast Snap pair resynchronization............................................................................................. 126
Pair resynchronization methods.....................................................................................126
Resynchronizing Fast Snap pairs.................................................................................. 127
4Contents

Assigning MU numbers to deleted snapshot data.................................................................... 127
Deleting snapshot data............................................................................................................. 128
Deleting Fast Snap pairs...........................................................................................................129
Accelerating the Fast Snap pair deletion process..........................................................130
Removing Fast Snap snapshot groups.......................................................................... 130
Assigning secondary volumes to Fast Snap pair snapshot data.............................................. 131
Assigning secondary volumes to snapshot data after creating new Fast Snap pairs.... 131
Assigning secondary volumes to snapshot data of existing Fast Snap pairs.................132
Releasing assignment of secondary volumes from Fast Snap pair snapshot data.................. 133
Changing assignment of secondary volumes to Fast Snap pair snapshot data....................... 134
Monitoring and maintaining Fast Snap.............................................136
Monitoring pair information....................................................................................................... 136
Viewing summary replication information.......................................................................136
Viewing local replication summary information.............................................................. 137
Viewing the number of pairs...........................................................................................139
Viewing the list of primary volumes................................................................................139
Viewing pair properties ..................................................................................................140
Fast Snap pair status definitions.................................................................................... 141
Viewing pair synchronization rates.................................................................................142
Monitoring consistency groups................................................................................................. 143
Viewing the number of consistency groups....................................................................143
Viewing the list of consistency groups............................................................................145
Viewing consistency group properties............................................................................145
Viewing Fast Snap pair task history..........................................................................................147
Fast Snap task code definitions..................................................................................... 149
Viewing licensed capacities...................................................................................................... 150
Viewing the number of cache management devices.................................................................150
Managing pools.........................................................................................................................151
Monitoring pool information............................................................................................151
Viewing used pool capacity ...........................................................................................153
Viewing formatted pool capacity and pool usage rates..................................................154
Increasing pool capacity.................................................................................................155
Decreasing pool capacity............................................................................................... 159
Editing the data pool warning threshold......................................................................... 163
Editing pool names.........................................................................................................165
Workflow for recovering blocked pools...........................................................................168
Workflow for decreasing pool capacity...........................................................................170
Managing virtual volumes......................................................................................................... 172
Editing virtual volume names......................................................................................... 172
Workflow for deleting V-VOLs specified for Fast Snap S-VOLs.....................................174
Viewing snapshot data capacity ...............................................................................................175
Maintaining pairs during storage system maintenance.............................................................176
Switching off the power supply.......................................................................................176
Definition of failure.................................................................................................................... 177
Troubleshooting Fast Snap................................................................178
Overview................................................................................................................................... 178
Failures in a cascaded configuration........................................................................................ 178
Troubleshooting the source of SIM codes.................................................................................179
Troubleshooting pools, pairs, and volumes related to Fast Snap............................................. 179
Workflow for correcting pool-related failures (SIM = 601xxx, 602xxx, 604xxx,
605xxx, and 606xxx)...................................................................................................... 184
Workflow for fixing errors when SIMs related to cache management devices are reported..... 190
Contents 5

Calculating the number of remaining cache management devices................................190
Workflow for fixing errors when pool-related SIMs are reported...............................................190
Completing SIMs ......................................................................................................................192
Automatic completion of SIMs........................................................................................192
Manually completing SIMs............................................................................................. 192
RAID Manager command reference for Fast Snap.......................... 194
Pair tasks using RAID Manager or Remote Web Console........................................................194
RAID Manager pair command results.......................................................................................195
Parameter ranges for RAID Manager options...........................................................................196
Troubleshooting with RAID Manager........................................................................................ 196
RAID Manager SSB2 codes...........................................................................................196
Notes on using Fast Snap primary volumes as Continuous Access Synchronous,
Business Copy, or Continuous Access Journal pair volumes........................................ 206
Fast Snap GUI windows and wizards................................................208
Replication window................................................................................................................... 208
Local Replication window..........................................................................................................211
View Pair Synchronization Rate window...................................................................................227
View Pair Properties window.....................................................................................................231
History window..........................................................................................................................238
Consistency Group Properties window..................................................................................... 240
Create FS Pairs wizard............................................................................................................. 244
Create FS Pairs window.................................................................................................244
Assign Secondary Volumes window.............................................................................. 253
Create FS Pairs confirmation window............................................................................ 260
Select Pool window...................................................................................................................267
Split Pairs wizard.......................................................................................................................269
Split Pairs window.......................................................................................................... 269
Split Pairs confirmation window..................................................................................... 272
Resync Pairs wizard..................................................................................................................274
Resync Pairs window..................................................................................................... 274
Resync Pairs confirmation window................................................................................ 277
Delete Pairs window................................................................................................................. 279
Edit Local Replica Options wizard............................................................................................ 281
Edit Local Replica Options window................................................................................ 281
Edit Local Replica Options confirmation window........................................................... 286
FS Pairs window....................................................................................................................... 287
Assign Secondary Volumes wizard...........................................................................................292
Assign Secondary Volumes window.............................................................................. 293
Assign Secondary Volumes confirmation window..........................................................299
Remove Secondary Volumes window.......................................................................................305
Websites.............................................................................................. 308
Support and other resources.............................................................309
Accessing Hewlett Packard Enterprise Support....................................................................... 309
Accessing updates....................................................................................................................309
Customer self repair..................................................................................................................310
Remote support........................................................................................................................ 310
Warranty information.................................................................................................................310
Regulatory information.............................................................................................................. 311
6Contents

Documentation feedback...........................................................................................................311
Contents 7

Overview of Fast Snap
About Fast Snap
To store snapshot data, you create a pair with a logical volume functioning as the P-VOL, and a virtual
volume as the S-VOL. A pair created to store snapshot data is referred to as a snapshot pair. A snapshot
pair displays showing the snapshot attribute.
When you create a Fast Snap pair, the status changes to "PAIR" and snapshot data is stored. You can
use Fast Snap to store a maximum of 1,024 snapshots of data (including the number of clones when you
clone a volume).
Updating the P-VOL first copies the differential data as snapshot data in pool volumes (pool-VOL), and
then updates the data. Snapshot data is a copy of differential data in Fast Snap P-VOLs. If your storage
system experiences a data storage failure, you can restore the data using the snapshot data in the pool.
Splitting a Fast Snap pair saves a snapshot and stops the copying of replaced data in the pool.
The following figure provides a basic illustration of storing snapshot data.
You can use snapshot data in open-system volumes.
More information
How Fast Snap uses V-VOLs on page 22
Splitting Fast Snap pairs to store snapshot data on page 120
Workflow for storing Fast Snap snapshot data
1. Create a Fast Snap pair. You can create a pair with the snapshot attribute (snapshot pairs). The pair is
in "PAIR" status.
2. The host updates the primary volume.
3. Split the snapshot pairs. The snapshot data of the primary volume is stored (Snapshot data A in the
figure below).
8 Overview of Fast Snap

4. The host updates the primary volume again.
5. Split the snapshot pairs. The updated data in the primary volume is stored as snapshot data
(Snapshot data B in the following figure). In the event of data corruption, you can recover using this
snapshot data.
The following figure illustrates how data in the pool is replaced.
NOTE: Because Snapshot data A and Snapshot data B are handled as a Fast Snap S-VOL of a snapshot
pair, the host can reference the P-VOL, Snapshot data A, and Snapshot data B.
Components of Fast Snap
Fast Snap components:
• Fast Snap pairs (clone and snapshot pairs).
• Volume related components (P-VOL, S-VOL, and pools)
• Snapshot tree related components (root volume, node volumes, and leaf volumes)
Groups:
• Consistency groups
• Snapshot groups
Software applications for XP7 Storage systems:
• Fast Snap
• Thin Provisioning (THP)
• RAID Manager
Components of Fast Snap 9

You can run RAID Manager commands to perform Fast Snap tasks (see Pair tasks using RAID
Manager or Remote Web Console on page 194). When using RAID Manager, run commands
directly from the host instead of using a management client.
10 Overview of Fast Snap

Fast Snap pairs
Type Volume that can
be used as P-VOL
Volume that can
be used as S-VOL
Cascade
capability
Description
Pairs with the
snapshot attribute
Logical volume
(LDEV)
Fast Snap V-VOL
(V-VOL of which
provisioning type is
Snapshot in RWC,
or V-VOL created
by the raidcom
add ldev -pool
snap command in
RAID Manager)
No Pairs used to store
snapshot data.
The logical volume
of the P-VOL
contains THP V-
VOLs (V-VOL of
which provisioning
type is Thin
Provisioning in
RWC, or V-VOL
created by the
raidcom add
ldev -pool
command in RAID
Manager).
THP V-VOL Yes Pairs used to store
snapshot data. To
create a cascaded
pair with the
snapshot attribute,
use a THP V-VOL
as the S-VOL. To
use a THP V-VOL
as the S-VOL,
make sure to
specify a cascaded
pair (with the
cascade attribute
enabled)
regardless of
whether it is in a
cascaded
configuration.
The logical volume
of the P-VOL
contains THP V-
VOLs (V-VOL of
which provisioning
type is Thin
Provisioning in
RWC, or V-VOL
created by the
raidcom add
ldev -pool
command in RAID
Manager).
Pairs with the clone
attribute
Logical volume
(LDEV)
THP V-VOL Yes Pairs to be cloned.
Fast Snap pairs 11

Type Volume that can
be used as P-VOL
Volume that can
be used as S-VOL
Cascade
capability
Description
The logical volume
of the P-VOL
contains THP V-
VOLs (V-VOL of
which provisioning
type is Thin
Provisioning in
RWC, or V-VOL
created by the
raidcom add
ldev -pool
command in RAID
Manager).
Volume components
Volume type Volumes that can be used Description
Primary Logical volume (LDEV) Logical volume of a P-VOL
contains THP V-VOLs (V-VOLs of
which provisioning type is Thin
Provisioning in RWC, or V-VOL
created by raidcom add ldev
-pool in RAID Manager).
Secondary Fast Snap V-VOL (V-VOL of
which provisioning type is
Snapshot in RWC, or V-VOL
created by raidcom add ldev
-pool snap in RAID Manager)
Use this volume to create
snapshot pairs. Cannot be used
for cascaded or cloned pairs.
This volume is required to create
a pair with the S-VOL specified.
THP V-VOL Use this volume to create
cascaded or cloned pairs.
This volume is required to create
a pair with the S-VOL specified.
Cloned pairs must be created
with the S-VOL specified.
When a THP V-VOL is used as
an S-VOL, you must specify a
cascaded or cloned pair.
Pool Logical volume (LDEV) Volumes that configure a pool
which stores snapshot data.
Differential data of a P-VOL is
stored in a pool volume as
snapshot data.
12 Volume components

Snapshot tree components
Volume type Volumes that can be used Description
Root Logical volume (LDEV) Volume (L1 pair of the P-VOL) in
the top layer of a snapshot tree.
The logical volume of the P-VOL
contains THP V-VOLs (V-VOL of
which provisioning type is Thin
Provisioning in RWC, or V-VOL
created by raidcom add ldev
-pool in RAID Manager).
Node THP V-VOL Volumes located between the
root volume and leaf volumes.
S-VOL of the root volume (or
another node volume), and the P-
VOL of a leaf volume (or another
node volume).
Leaf THP V-VOL Volumes in the bottom layer of a
snapshot tree.
S-VOL of the root volume or a
node volume, which is not a P-
VOL of any pair.
Maximum number of Fast Snap pairs
The maximum number of pairs that can be created on the XP7 storage system is 1,048,575.
Consistency and snapshot groups
A consistency group can include Fast Snap (FS), Business Copy (BC), and Business Copy MF (BC MF)
pairs. Use consistency groups to split the Fast Snap pairs that are defined in the group. Splitting the pairs
using the group assures data consistency at the time the XP7 Storage system receives the request.
A snapshot group is a group of only Fast Snap pairs. Use consistency or snapshot groups to perform Fast
Snap tasks on all of the pairs within the group. You define Fast Snap pairs to a snapshot group when you
create the pairs.
The following table shows the differences between consistency groups and snapshot groups.
Item Consistency group Snapshot group
Pair limit per group 8,192 8,192
Limit 2,048 2,048
Data consistency Guaranteed Not guaranteed
Software application from which you can define pairs FS, BC, and BC MF FS
For more information about defining Cnt Ac-S pairs in consistency groups, see the HPE XP7 Continuous
Access Synchronous User Guide.
Snapshot tree components 13

For more information about defining Cnt Ac-J pairs in consistency groups, see the HPE XP7 Continuous
Access Journal User Guide.
For more information about defining BC pairs in consistency groups, see the HPE XP7 Business Copy
User Guide.
More information
Workflow for creating groups and storing snapshot data using RAID Manager on page 26
Adding Fast Snap pairs to snapshot or consistency groups using RAID Manager on page 119
Removing Fast Snap snapshot groups on page 130
Pair tasks using RAID Manager or Remote Web Console on page 194
Snapshot Clones
When distributing data in a storage system, you can use clones to improve efficiency.
The following figure illustrates cloning.
When cloning pairs, use a logical volume as the P-VOL and a THP V-VOL as the S-VOL.
If you split pairs that have the clone attribute, the data of the entire P-VOL is copied to the S-VOL
asynchronously to create a clone of the primary volume. When the copy completes, pairs are deleted and
the S-VOL is unpaired (becomes a THP V-VOL). This volume can be used as a volume in the same
status as the P-VOL. This operation is referred to as cloning pairs.
A maximum of 1,024 clones (including the number of snapshots if you store them) can be created by
using Fast Snap.
Cloning pairs includes operations after the P-VOL is copied to the S-VOL, until volumes are unpaired.
Volumes created by cloning are not included.
Snapshot trees and cascaded pairs
The volume in the top layer of the snapshot tree is the root volume. Volumes in the bottom layer are leaf
volumes.
14 Snapshot Clones

Creating cascaded pairs
Fast Snap S-VOLs can be paired with secondary layer S-VOLs. First layer (L1) S-VOLs can also be
paired with secondary layer (L2) S-VOLs. A maximum of 64 layers can be created, and a maximum of
1,024 S-VOLs can be used for a P-VOL. In this case, the snapshot tree is cascaded.
L2 to L64 pairs are called cascaded pairs. The following figure illustrates the configuration of cascaded
snapshot trees.
Creating cascaded pairs 15

• The volume in the top layer of the snapshot tree (P-VOL of the L1 pair) is the root volume.
• Volumes between the root and leaf volumes are node volumes.
• Volumes in the bottom layer of the snapshot tree are leaf volumes.
To create a Fast Snap pair that can be used in a cascaded snapshot tree, open the Create FS Pairs
window and select Enable for Cascade in RWC or use the raidcom add snapshot -snap_mode
cascade command in RAID Manager. For details, see Creating Fast Snap pairs using Remote Web
Console on page 114 or Adding Fast Snap pairs to snapshot or consistency groups using RAID
Manager on page 119.
When the S-VOL of a Fast Snap pair you created for a P-VOL for the first time is a THP V-VOL, you can
create cascaded pairs. If a Fast Snap pair whose secondary volume is a Fast Snap V-VOL (which has the
Snapshot provisioning type) is created, remove the pair first, and then create another Fast Snap pair
whose secondary volume is a THP V-VOL.
16 Overview of Fast Snap

A snapshot tree can be configured by combining snapshot and cloned pairs. As shown in the following
figure, you can also cascade pairs that are being cloned, but you can only clone up to three pairs
concurrently. The following figure shows an example of when pairs that are being cloned are also
cascaded.
You can use the S-VOL of a cascaded and cloned pair as a new L1 pair of the P-VOL. In this case, the
volume is the root volume, and a node or leaf volume.
Volume differences between Fast Snap and Business Copy
The following table summarizes the volume and other differences between Fast Snap and Business
Copy.
Volume differences between Fast Snap and Business Copy 17

Item Fast Snap Business Copy
Initial copy operation Not required.
Volumes can be copied faster.
Required.
Number of S-VOLs per P-VOL Up to 1,024 Up to 9
Capacity efficiency High. Only differential data is
copied from the P-VOL.
Low. The entire P-VOL is copied.
Operation of copied volumes Always used with the P-VOL. Can be used separately from the
P-VOL.
P-VOL physical failures S-VOL data cannot be
guaranteed.
P-VOL data can be restored
using the S-VOL.
S-VOL or pool physical failures If a physical failure occurs in a
pool*, data in all S-VOLs that use
the pool cannot be guaranteed.
If a physical failure occurs in an
S-VOL, data in the S-VOL cannot
be guaranteed.
*When a pool is full (the depletion threshold is exceeded in a pool for which the capacity for Fast Snap
pairs is limited), data in all S-VOLs using the pool cannot be guaranteed.
The following figures explain the relation of data when a failure occurs in the P-VOL.
Fast Snap S-VOLs reference data in the P-VOL. Therefore, if a failure occurs in the P-VOL, data in all S-
VOLs under the P-VOL is lost.
18 Overview of Fast Snap

Business Copy S-VOLs retain all P-VOL data. Therefore, if a failure occurs in the P-VOL, data in the S-
VOLs is not lost.
The following figure explains the relation of data when a failure occurs in a pool.
Fast Snap S-VOLs reference data in the pool. If the pool cannot be used because a failure occurs in the
pool or the pool becomes full, data in all S-VOLs that use the pool is lost. In addition, if a pool failure
occurs or the pool becomes full during restoration, data in the P-VOL which is being restored cannot be
used.
The following figure explains the relation of data when a failure occurs in an S-VOL.
Overview of Fast Snap 19

For Business Copy, each S-VOL independently retains data. Therefore, only data in the failed S-VOL is
affected. In addition, if a failure occurs in an S-VOL during restoration, data in the P-VOL which is being
restored cannot be used.
XP7 Storage software applications for Fast Snap
Fast Snap
Use the Fast Snap software on the Remote Web Console (RWC) computer that is connected to the
service processor (SVP) by means of the TCP/IP local area network (LAN).
Thin Provisioning
Use the THP software on the RWC computer. A user license is required to use THP.
Since Fast Snap uses a portion of the THP licensed capacity for its pool capacity, reserve enough THP
licensed capacity to run both THP and Fast Snap and to accommodate the Fast Snap pairs or pools that
you will create.
Fast Snap and THP pool-VOLs are also referred to as used volumes. The licensed capacity must exceed
the total capacity of used volumes.
RAID Manager
When you use RAID Manager to define multiple Fast Snap pairs in a consistency group, you can only
specify one consistency group for a group defined by the configuration definition file for RAID Manager.
NOTE: The configuration definition file for RAID Manager is a group that is not a consistency group.
If you create a new pair and define the pairs in a consistency group for a group you defined using the
configuration definition file for RAID Manager, and the pair is already defined in a consistency group, the
pair is defined in the same consistency group even if you try to create a new pair and assign it to a
different consistency group.
More information
Splitting Fast Snap pairs to store snapshot data using RAID Manager on page 121
20 XP7 Storage software applications for Fast Snap