Dell EMC Unity™ Family

Notes, cautions, and warnings

? NOTE: A NOTE indicates important information that helps you make better use of your product.

⚠️ CAUTION: A CAUTION indicates either potential damage to hardware or loss of data and tells you how to avoid the problem.

❗ WARNING: A WARNING indicates a potential for property damage, personal injury, or death.

© 2016-2021 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other trademarks are trademarks of Dell Inc. or its subsidiaries. Other trademarks may be trademarks of their respective owners.

Preface

As part of an improvement effort, revisions of the software and hardware are periodically released. Therefore, some functions described in this document might not be supported by all versions of the software or hardware currently in use. The product release notes provide the most up-to-date information on product features. Contact your technical support professional if a product does not function properly or does not function as described in this document.

Where to get help

Support, product, and licensing information can be obtained as described below.

Product information

For product and feature documentation or release notes, go to Unity Technical Documentation at: dell.com/unitydocs.

Troubleshooting

For information about products, software updates, licensing, and service, go to Support (registration required) at: dell.com/support. After logging in, locate the appropriate product page.

Chapter 1: Configuring LUNs and consistency groups

Topics:

• About LUN storage
• Create a LUN
• Change LUN or LUN thin clone properties
• Delete a LUN
• About iSCSI interfaces
• Create a consistency group
• Add a LUN to a consistency group
• Change consistency group or consistency group thin clone properties
• Delete a consistency group

About LUN storage

LUN storage resources provide hosts with access to general-purpose block-level storage through network-based iSCSI or Fibre Channel (FC) connections. With LUN storage, you can manage addressable partitions of block storage resources so that host systems can mount and use these resources (LUNs) over FC or IP connections. After a host connects to the LUN, it can use the LUN like a local storage drive.

Figure 1. LUN storage overview

This diagram illustrates the connection between storage hosts and the storage system for LUN access. It shows two storage hosts, Host1 and Host2, each connected to the storage system. Host1 uses Fibre Channel (FC) for access, connecting via an FC initiator (WWN) to a LUN labeled 'Host1_E (LUN 1)' within the 'Storage resource (Host1 storage)' on the storage system. Host2 uses iSCSI for access, connecting via an iSCSI initiator (iSCSI IQN) to two LUNs: 'Host2_E (LUN 2)' and 'Host2_F (LUN 3)', both within the 'Storage resource (Host2 storage)' on the storage system. The diagram highlights the network connection pathways, including an FC Port (I/O Module) and an iSCSI interface (iSCSI Target: IQN), demonstrating how hosts can mount and use LUNs as local storage drives.

Each interface has a unique VLAN ID (checked locally for the port) and an IP address (checked locally for the storage system) for iSCSI connections, and a World Wide Name (WWN) for FC connections.

? NOTE: Different physical network ports can have the same VLAN ID.

Table 1. Components of LUN storage

Storage hosts (Initiators)

Storage hosts are systems that use storage system LUN resources. Before a host can access storage resources, you must define a configuration for it through Unisphere with the Host wizard. A host configuration specifies the hostname and one or more initiators (FC WWN or iSCSI IQN). After defining the host configuration, you can also specify the type of access that the host has to the LUN or consistency group. The host can then map from the host-side to any LUNs associated with a consistency group. See the host documentation for more information.

Create a LUN

Prerequisites

Before you create a LUN, at least one pool must exist on the storage system. Obtain the following information:

• Storage size you want to allocate for the LUN.
• Information about the host that will use the LUN (if a host configuration does not exist), including the host's iSCSI address or WWN, CHAP secret (if applicable), and type of access (storage, snapshot, or both) to allow.
• Protection schedule including the frequency with which to perform automatic snapshots and the length of time to retain individual snapshots.

About this task

Steps:

1. Under Storage, select Block > LUNs.
2. Select the [Add icon].

? NOTE: You can also create LUNs when you create a new consistency group.

3. Specify the relevant information, while noting the following:

• You can specify a Host LUN ID of your choosing. If one is not specified, the system will assign one by default.
• If you are adding LUNs from the Host Properties window, you can specify Host LUN IDs when creating new LUNs by using the Assign Host LUN IDs button. You cannot specify Host LUN IDs when adding existing or multiple LUNs to the host, but you can modify them after they are added to the host.
• After you create the LUN, you can increase its size but not decrease it.
• You can create multiple LUNs at once with a maximum limit of 100 LUNs. The system appends the LUN name with a number when creating multiple LUNs.

• The Size value displays the quantity of storage subscribed for the LUN.
• If you want to limit I/O throughput and bandwidth to provide more predictable performance, select an existing host I/O limit policy to enforce on this LUN or create a new policy.
• The Thin checkbox is selected by default. If you do not want to create a thin LUN, remove the checkmark from the Thin checkbox. Removing the checkmark also disables the Data Reduction option.
• The Data Reduction checkbox is available for thin LUNs in All-Flash pools only. It allows a thin LUN to have data reduction applied to save space.
• The Advanced Deduplication checkbox becomes available only when the Data Reduction checkbox is enabled. It provides the ability to reduce the amount of data storage needed by eliminating redundant data from the system. Once enabled, all incoming writes to the system will have advanced deduplication applied.

Advanced Deduplication is available on:

• Dynamic or Traditional pools in Unity 380F, 480F, 680F, and 880F systems
• Dynamic pools in Unity All-Flash 450F, 550F, and 650F systems
• All-Flash pools in Unity Hybrid 380, 480, 680, and 880 systems

• If a resource contains snapshots or thin clones, either data reduction or both data reduction and advanced deduplication might be enabled on the snapshots or thin clones, depending on the source's settings.

Change LUN or LUN thin clone properties

Steps:

1. Under Storage, select Block > LUNs.
2. Select the relevant LUN or thin clone, and then select the [Edit icon].
3. On the General tab:
   • Change the LUN or thin clone name, description, and size, and view space usage and capacity information.
   • You can change the default SP owner for a LUN, but not for a thin clone.
   • If you change the default SP owner for a base LUN, the default SP changes automatically for its derivative thin clones.
   • If this is a thin LUN or a file system in an All-Flash pool, you can choose to apply data reduction to all incoming writes by selecting the Data Reduction checkbox.

? NOTE: To apply data reduction to both incoming LUN writes and existing LUN data, you must use the LUN Move session feature to move the LUN's data to a destination LUN that has data reduction enabled. It is recommended that you perform a LUN Move operation only on a single LUN for an SP at a time, and not perform multiple move operations on an SP simultaneously. Refer to About LUN Move sessions for additional LUN Move information.

• You can also enable Advanced Deduplication if the Data Reduction checkbox is enabled. Advanced deduplication provides the ability to reduce the amount of data storage needed by eliminating redundant data from the system. Once enabled, all incoming writes to the system will have advanced deduplication applied.

Advanced deduplication is available only on:

• Dynamic or Traditional pools in Unity 380F, 480F, 680F, and 880F systems
• Dynamic pools in Unity All-Flash 450F, 550F, and 650F systems
• All-Flash pools in Unity Hybrid 380, 480, 680, and 880 systems

• If the LUN already has data reduction applied, you can view the capacity: how much space is allocated after data reduction was applied, and the space saved due to applying data reduction to this LUN, including its snapshots and thin clones. Data reduction savings are shown in multiple formats, including actual space saved (GB/TB), ratio, and percentage.
• You can also choose to disable data reduction by removing the checkmark from the Data Reduction checkbox and clicking the Apply button. Existing data remains as is until overwritten. Any newly-written data does not have data reduction applied.
• You can also choose to disable advanced deduplication by removing the checkmark from the Advanced Deduplication checkbox and clicking the Apply button. Existing data remains as is until overwritten. Any newly-written data does not have advanced deduplication applied.
• A thin clone cannot have data reduction applied independently of its base LUN. However, if you apply data reduction to the base LUN, the thin clone also has data reduction applied.
• If a LUN is in the process of being moved, you can view the status and change the move session's priority setting. If the move is completed, you can view the move status for up to three days after the operation completed.

? NOTE: A thin clone or a LUN that has a thin clone cannot be moved.

1. On the Host Access tab, modify the list of hosts that have access to the LUN or thin clone, modify the Host LUN ID for a specific host, or change the type of access.
2. On the FAST VP tab, change the tiering policy and view the data distribution per tier.

? NOTE: You cannot change the tiering policy for a thin clone independently of its base LUN. However, if you change the tiering policy of the base LUN, the thin clone inherits the changed tiering policy.

1. On the Snapshots tab, manage the LUN or thin clone's snapshots or configure a snapshot schedule for the LUN.
2. On the Replication tab, configure replication settings. Select Configure Replication to get started.

? NOTE: When you replicate a thin clone, it becomes a standard LUN on the destination storage system, with no ties to the original base LUN.

1. On the Host I/O Limit tab, view the bandwidth and throughput performance of the LUN or thin clone with the current policy, select a different policy and preview the performance impact of that policy, or apply a new policy.

Delete a LUN

Prerequisites

You should delete a LUN only if:

• The LUN was used for testing purposes and the tests have completed.
• The LUN has been replicated to a different destination and the source LUN is no longer needed.
• You are trying to save space by deleting the LUN and the data on that LUN is no longer needed.

? NOTE: LUN deletion is an irreversible operation.

About this task

Ensure the following conditions are met before attempting to delete a LUN:

• The LUN does not have any attached snapshots.
• The LUN does not have any active replication sessions.
• The LUN is not currently attached to hosts.

? NOTE: LUNs cannot be deleted if hosts are currently attached. Remove host access before deleting any LUNs. Plan host downtime where needed, or ensure the hosts no longer need the LUN before removing access. If you are migrating hosts from one LUN to another, ensure the hosts have access to the new LUN before removing them from the LUN that will be deleted.

Steps:

1. Under Storage, select Block > LUNs.
2. Select the relevant LUN, and click the [Delete icon].

If the Delete icon is not available, the LUN currently has hosts attached. Use the following steps to remove access from the LUNs and retry the deletion:

1. Make sure the LUN you want to delete is selected.
2. Ensure any currently attached hosts no longer need the LUN. Under [More Actions], click Modify Host Access.
3. Review the list of attached hosts. Select all the hosts, click the [Delete icon], and then click Delete to confirm.

When the job completes, the Delete icon will become available for the selected LUN.

Results

If the job fails, check the job details on the Jobs page for more information. The LUN deletion may be prevented due to one of the scenarios listed above.

About iSCSI interfaces

iSCSI interfaces enable hosts using the iSCSI protocol to access block storage (LUNs, consistency groups, and VMware VMFS datastores) on the storage system. The iSCSI interfaces provide continuous access to data when a Storage Processor (SP) becomes unavailable because of a system software upgrade or component failure. When you add an iSCSI interface on the storage system, you associate it with one or both Storage Processors (SPs). So, at a given point, there will be multiple iSCSI interfaces on each SP. These become the available paths hosts, with relevant access privileges, can use to access the relevant storage resources.

? NOTE: Fibre Channel interfaces are created automatically on the storage system.

To ensure continuous access to the storage in an event of a failover, set up iSCSI interfaces on the same port of each SP, and then leverage host-based multipathing software to manage multiple connections to the storage system.

Add or edit iSCSI interfaces

When you log on to Unisphere for the first time, the Initial Configuration Wizard includes a step that enables you to add iSCSI interfaces. To add or manage iSCSI interfaces at a later time, under Storage, select Block > iSCSI Interfaces.

? NOTE: iSCSI interfaces can only be created on an Ethernet port that is not participating in a link aggregation.

Before you begin creating or updating an iSCSI interface, ensure that you have the following information:

• The Ethernet port you will use for the iSCSI interface.
• For each Storage Processor (SP), the following address information:
  • IP address associated with the iSCSI interface. Although you can specify an IPv4 or IPv6-based address, ensure that you specify the same type of address for both SPs.
  • IP address mask or prefix length that identifies the subnet where the iSCSI interface resides.
  • Gateway IP address associated with the iSCSI interface.
• Alias name associated with the IQN. The IQN and the IQN alias are associated with the port, and not the iSCSI interface. When you change the IQN alias for an iSCSI interface, the alias changes for all interfaces on that port.
• If applicable, the VLAN ID (between 1 and 4904) you want to associate the iSCSI interface with.

? NOTE: For the network to continue functioning properly, ensure that you set the VLAN ID only when you have configured the network switch port to support VLAN tagging of multiple VLAN IDs.

Create a consistency group

Steps:

1. Under Storage, select Block > Consistency Groups.
2. Select the [Add icon].
3. Specify the relevant information.

Add a LUN to a consistency group

Steps:

1. Under Storage, select Block > Consistency Groups.
2. Select a consistency group from the list.
3. Select Add LUNs.
4. Specify the relevant information, while noting the following:
   • You can create one or more new LUNs and add them to the consistency group.
   • Or you can move existing LUNs that are not already assigned to a consistency group to a consistency group.

Change consistency group or consistency group thin clone properties

Steps:

1. Under Storage, select Block > Consistency Groups.
2. Select the relevant consistency group or thin clone, and then select the [Edit icon].
3. On the General tab, change a consistency group or thin clone name and description. and view space usage and capacity information.
4. On the LUNs tab, add or remove LUNs from the consistency group or thin clone. You can change the default SP owner for a LUN, but not for a thin clone. If you change the default SP owner for a base LUN, the default SP changes automatically for its derivative thin clones.

If this is a thin LUN in an All-Flash pool, you can choose to apply data reduction to all incoming writes by selecting the Data Reduction checkbox.

? NOTE: To apply data reduction to both incoming LUN writes and existing LUN data, you must use the LUN Move session feature to move the LUN's data to a destination LUN that has data reduction enabled. It is recommended that you perform a LUN Move operation only on a single LUN for an SP at a time, and not perform multiple move operations on an SP simultaneously. Refer to About LUN Move sessions for additional LUN Move information.

• If the LUN already has data reduction applied, you can view the capacity: how much space is allocated after data reduction was applied, how much space is not allocated, and the space saved for the entire system after data reduction.
• You can also choose to disable data reduction by removing the checkmark from the Data Reduction checkbox and clicking the Apply button. Existing data remains as is. Any newly-written data does not have data reduction applied.
• If a LUN is in the process of being moved, you can view the status and change the move session's priority setting. If the move is completed, you can view the move status for up to three days after the operation completed.
• A thin clone cannot have data reduction applied independently of its base LUN. However, if you apply data reduction to the base LUN, the thin clone also has data reduction applied.

1. On the Access tab, modify the list of hosts that have access to the LUNs in the consistency group or thin clone, or change the type of access.
2. On the FAST VP tab, change the tiering policy and view the data distribution per tier.

? NOTE: You cannot change the tiering policy for a thin clone independently of its base LUN in the consistency group. However, if you change the tiering policy of the base LUN, the thin clone inherits the changed tiering policy.

1. On the Snapshots tab, manage the consistency group's or thin clone's snapshots or configure a snapshot schedule for the LUN or thin clone.
2. On the Replication tab, configure replication settings. Select Configure Replication to get started.

? NOTE: When you replicate a thin clone, it becomes a standard LUN on the destination storage system, with no ties to the original base LUN.

Delete a consistency group

Prerequisites

? NOTE: Deleting a consistency group will also delete any of its snapshots, as well as all of the LUNs in that group. If the consistency group contains LUNs with attached hosts, you cannot delete the consistency group.

Steps

1. Under Storage, select Block > Consistency Groups.
2. Select the relevant consistency group, and then select the [Delete icon].

If the Delete icon is not available, one or more of the LUNs in the consistency group currently has hosts attached. Remove access from the group LUNs and retry the deletion:

1. Select the consistency group you want to delete.
2. Ensure any currently attached hosts no longer need the LUNs in the consistency group. Under [More Actions], click Remove Host Access.
3. Review the list of attached hosts for each LUN in the consistency group. Click Remove Host Access to confirm.

When the job completes, the Delete icon will become available for the selected consistency group.

Results

If the job fails, check the job details on the Jobs page for more information. The consistency group deletion may have been prevented if any LUNs within it have attached hosts.

Chapter 2: Configuring LUN move

Topics:

• About LUN Move sessions
• LUN move session restrictions and limitations
• Create a LUN move session
• Cancel a LUN move session
• Best practices for LUN move sessions
• Troubleshooting LUN move session issues

About LUN Move sessions

The LUN Move feature lets you move block storage resources:

• To a pool with faster drives.
• Between pools for load balancing.
• To take advantage of newly purchased spindles.
• To convert a thin LUN to a thick LUN, or a thick LUN to a thin LUN.
• To enable data reduction (for either newly-written data or both newly-written data and existing data) on a thin LUN in an All-Flash pool. If you choose to apply data reduction to existing data, choose the pool where you want to move the LUN data.

You can move LUNs, member LUNs in a consistency group, and VMware VMFS LUNs. However, you cannot move thin clones or storage resources that have derived thin clones.

? NOTE: If LUNs have associated snapshots, the snapshots are deleted once the move completes successfully.

While a storage resource is being moved, you can view the status from the storage resource's summary and properties pages. Once completed, the move status can be viewed for up to three days from the same two pages.

LUN move session restrictions and limitations

A LUN move session cannot start if:

• A storage system NDU is in progress.
• The destination pool does not have enough space.
• A LUN expand or shrink operation is in progress.
• The source LUN is being restored from a snapshot.
• An import from a VNX LUN to the source LUN is in progress.
• The source LUN is flagged as requiring recovery.
• The source LUN is offline.
• Replication is enabled, and the LUN is a replication source or destination. Turn off replication prior to starting a move session.

During a LUN move session, you cannot:

• Delete the source LUN.
• Create a snapshot of the source LUN.
• Restore the source LUN from a snapshot.
• Add or remove the source LUN from a consistency group.
• Start an import from a VNX LUN to the source LUN.
• Perform an expand or shrink operation on the source LUN.
• Start an NDU of the storage system.
• Start a recovery operation on the source LUN.
• Configure a LUN for replication.

Create a LUN move session

Prerequisites

Be aware that a LUN move session cannot start if:

• A storage system NDU is in progress.
• The destination pool does not have enough space.
• A LUN expand or shrink operation is in progress.
• The source LUN is being restored from a snapshot.
• An import from a VNX LUN to the source LUN is in progress.
• The source LUN is flagged as requiring recovery.
• The source LUN is offline.
• Replication is enabled, and the LUN is a replication source or destination. Turn off replication prior to starting a move session.

See LUN move session restrictions and limitations for additional details.

About this task

Steps:

1. Under Storage, select Block > LUNs.
2. Select More Actions > Move.
3. On the Move LUN window, specify the relevant information.
4. Click OK.

? NOTE: If the source LUN contains snapshots, a warning is issued, and the move continues. Once the move completes successfully, the system deletes the snapshots. You can then create snapshots on the new LUN.

Cancel a LUN move session

Prerequisites

A LUN move session must be in progress to be cancelled.

About this task

Steps:

1. Under Storage, select Block > LUNs.
2. Select More Actions > Cancel Move.
3. Click Yes.

Best practices for LUN move sessions

The following describes best practices to be aware of when moving LUNs in a system:

1. You should properly plan the migration before the move. For example, determine the new storage requirements, locate the destination storage pool, and determine if the pool is suitable (for example, that there is enough space available).
2. Be aware that no manual cut over is required. Once the move operation starts, the system will cutover to the new storage automatically at the completion of a successful move.
3. Be aware of the move session priority option. The priority of a session indicates the amount of resources devoted to that session compared to other move sessions. It does not pertain to the throttle of a session.

Troubleshooting LUN move session issues

The following table describes common issues that can occur during a LUN move operation, and how to resolve them.

Table 2. LUN move troubleshooting information

Chapter 3: Configuring block thin clones

Topics:

• About thin clones
• Thin clone terminology and hierarchy
• Create a thin clone
• Change thin clone properties
• Refresh a thin clone

About thin clones

A thin clone is a read-write copy of a thin block storage resource (LUN, consistency group, or VMFS datastore) that shares blocks with the parent resource. Data available on the source snapshot at the moment of the thin clone creation is immediately available to the thin clone. The thin clone references the source snapshot for this data. However, data resulting from changes to the thin clone after its creation is stored on the thin clone. Changes to the thin clone do not affect the source snapshot, because the source snapshot is read-only.

Advantages of using thin clones

Thin clones allow you to create and manage space-efficient copies of production environments, which is beneficial for the following types of activities:

• Development and test environments - Thin clones allow development and test personnel to work with real workloads and use all data services associated with production storage resources without interfering with production. They also allow development personnel to promote a test thin clone to production.
• Parallel processing - Parallel processing applications that span multiple servers can use multiple thin clones of a single production data set to achieve results more quickly.
• Online backup - You can use thin clones to maintain hot backup copies of production systems. If there is corruption in the production data set, you can immediately resume the read-write workload by using the thin clones.
• System deployment - You can use thin clones to build and deploy templates for identical or near-identical environments. For example, you can create a test template that is cloned as needed for predictable testing.

Thin clone restrictions

The following restrictions apply to thin clones:

• Thin clones are not supported for snapshots of thick LUNs.
• When you create a thin clone, the source snapshot for the clone must be read-only, and it cannot have automatic snapshot deletion or a snapshot expiration policy enabled.
• After you create a thin clone, the source snapshot can be deleted.
• You cannot create a thin clone of a thin clone without first creating an intermediate snapshot.
• A thin clone becomes a full clone on the destination storage system when it is replicated.
• You cannot delete a base storage resource (production resource) when it has thin clones.
• You cannot move a thin clone.

Thin clone terminology and hierarchy

The snapshots and thin clones for a LUN, consistency group, or VMware VMFS datastore form a hierarchy. This document uses the following terms to describe this hierarchy:

Source snapshot

A snapshot of a LUN, consistency group, or VMFS datastore used as the source for thin clone create and refresh operations.

Base LUN, base consistency group, base VMFS datastore

The founding (production) LUN, LUN group, or VMFS datastore for a set of derivative snapshots and thin clones.

Base LUN family, base consistency group family, base VMFS datastore family

A LUN, consistency group, or base VMFS datastore and all of its derivative thin clones and snapshots. This includes snapshots and thin clones based on child snapshots of the storage resource or its thin clones, and so forth.

Original parent resource

The original parent datastore or thin clone for the snapshot on which the thin clone is based. This resource does not change when a thin clone is refreshed to a different source snapshot, because the new source snapshot must be in the same base LUN, consistency group, or VMFS datastore family.

For example, suppose the following hierarchy of snapshots and thin clones exists for LUN 1:

Figure 2. A thin clone hierarchy

This diagram depicts the hierarchical relationship between a base LUN, its snapshots, and derived thin clones. It starts with 'LUN 1'. From 'LUN 1', 'Snapshot 1' and 'Snapshot 2' are created. 'Snapshot 1' serves as the source for 'Thin Clone 1', with data flowing from the snapshot to the clone. 'Snapshot 2' serves as the source for 'Thin Clone 2', also with data flow. 'Snapshot 3' is derived from 'Snapshot 2'. 'Snapshot 3' then serves as the source for 'Thin Clone 3'. An arrow labeled 'Refresh action' points from 'Thin Clone 3' back to 'Snapshot 1', indicating that 'Thin Clone 3' can be refreshed using 'Snapshot 1' as its new data source. The diagram explains how changes to a thin clone do not affect its source snapshot, and how refresh operations update a thin clone with data from a different snapshot within the same family.

The base LUN family for LUN 1 includes all of the snapshots and thin clones shown in the diagram. For Thin Clone 2:

• The source snapshot is Snapshot 2.
• The base resource is LUN 1.
• The original parent resource is LUN 1.

For Thin Clone 3:

• The source snapshot is Snapshot 3.
• The base resource is LUN 1.
• The original parent resource is Thin Clone 2.

Now, if Thin Clone 3 is refreshed to Snapshot 1:

• The source snapshot changes from Snapshot 3 to Snapshot 1.
• The base resource is still LUN 1.
• The original parent resource is still Thin Clone 2.

If Thin Clone 2 is deleted after Thin Clone 3 is refreshed, the original parent resource shows as empty.

Create a thin clone

About this task

You can create thin clones for LUNs, consistency groups, and VMware VMFS datstores.

Steps:

1. Locate the summary page for the storage resource you want to clone.
2. Select the storage resource, and then select More Actions > Clone.
3. Select whether you want to create the thin clone from an existing or newly-created snapshot. To create the thin clone from an existing snapshot, select the snapshot.
4. On the Configure page, specify the relevant information, and optionally select Create I/O Limit to create a new I/O limit policy for the thin clone.
5. Continue following the steps in the wizard to optionally configure host access, a snapshot schedule, and replication for the thin clone. You can configure these features now or at a later time.

Change thin clone properties

Steps:

1. Locate the summary page for the storage resource associated with the thin clone you want to modify.
2. Select the relevant thin clone, and then select the [Edit icon].
3. On the General tab, change the name, description, and size of the thin clone.
4. On the Host Access tab, modify the list of hosts that have access to the thin clone, or change the type of access.
5. On the FAST VP tab, view the data distribution per tier.
6. On the Snapshots tab, manage the thin clone's snapshots or configure a snapshot schedule for the thin clone.
7. On the Replication tab, configure replication settings. Select Configure Replication to get started.
8. On the Host I/O Limit tab, view the bandwidth and throughput performance of the thin clone with the current policy, select a different policy and preview the performance impact of that policy, or apply a new policy.

Refresh a thin clone

About this task

Refreshing a thin clone updates the thin clone's data with data from a different source snapshot. The new source snapshot must belong to the thin clone family; that is, it must be related to the base LUN, base consistency group, or base VMware VMFS datastore for the existing thin clone. In addition, it must be read-only, and it cannot have automatic snapshot deletion or a snapshot expiration policy enabled.

When you refresh a thin clone, the existing data is removed from the thin clone and the data from the new source snapshot is copied to it. If the thin clone has derivative snapshots, they remain unchanged, and the family hierarchy stays intact.

? NOTE: You can promote a test thin clone to production by refreshing the base storage resource with the thin clone's snapshot. This provides the ability to refresh production environments based on factors such as performance tuning, query optimization, and bug fixes. It is strongly recommended to disable base the base LUN's host access before this performing this operation.

Steps:

1. Locate the summary page for the source storage resource whose thin clone you want to refresh.
2. Select the relevant thin clone, and then select More Actions > Refresh.
3. Select whether you wan create a snapshot of thin clone before it refreshes.

? NOTE: It is recommended that you leave the default, which is to have the system create a copy of the thin clone before refreshing.

1. Select the source snapshot for the refresh.