Synology Administrator's
Guide for

UC32001

Table ofContents

Introduction 	

01

Quick Start 	

03Manage Users
Modify Network Settings
Deploy Storage SpaceManage iSCSI Services
Back Up and Recover Data
Monitor Overall System Status

Optimal UC3200 Deployment 	

16

UC3200 Deployment
Initiator Deployment

UC3200 Deployment after the RMA 	

21

If a controller is replaced through the RMA
If the entire UC3200 is replaced through the RMA

Conclusion 	

23

Introduction

Introduction

Synology is committed to developing a storage solution to meet the growing business needsfor deploying virtualization applications and environments. Designed with the concept ofservice continuity and zero downtime at its core, Synology Unified Controller UC3200 comeswith active-active controllers to ensure that one controller can immediately take over all
services if the other controller breaks down.
UC3200 supports a SAS interface, which requires the installation of SAS drives, to provide
non-disruptive iSCSI storage services. This device also guarantees flexible storage space
deployment and disaster recovery solutions, allowing users to build the most reliablevirtualization platform. Please see the following for the key features of UC3200:

Key Features of UC3200• Designed with active-active controllers to ensure one controller takes over the other in theevent of controller failure.
• Built-in SATA-DOM to provide highly reliable and optimal performance for the operating
system DSM UC.
• Expandable up to two expansion units (i.e., RXD1219sas) to flexibly add 24 drives for storage
capacity allocation.
• Supports the Btrfs file system to schedule and take up to 4,096 snapshots for LUN
protection.
• Protects LUNs by replicating LUN snapshots to another Synology Unified Controller or
Synology NAS (DSM 6.2.2 or versions above).
• Supports Self-Encrypting Drive (SED) to enhance data security.
• Offers an intuitive and web-based interface for easy system deployment.
• Supports automatic network failover and iSCSI Multipath I/O (MPIO).
• Ensures non-disruptive iSCSI services by transferring from one controller to the other within
30 seconds.1• Protects data in memory cache to guarantee data integrity.
• Enhances system stability through the pre-installed operating system in SATA DOM (Disk on
Module) for isolating the operating system and services.

1 The 30-second transfer time is obtained from Synology's performance test. However, the actual required time may differ in different environments.

01

Introduction

Get Started with UC3200
Once the hardware setup is complete, please follow the steps below to sign in to DSM UC:
1. Power on your UC3200.2
2. Open a web browser on a computer in the same network as your UC3200.3
3. Enter find.synology.com into the address bar of your web browser.
4. Web Assistant will be launched in your web browser. It will search for and find theSynology Unified Controller within the local network. The status of your UC3200 should be
Ready.
5. Select a controller and click Connect to start the setup process and follow the onscreen
instructions.4
6. Create your administrator account and click Next.
7. Select an option for DSM UC update and maintenance. Click Next.
8. Create a new Synology Account or use an existing account. Click Next.
9. Set the static IP address for the LAN port currently in use to enable network failover
automatically.
10. Tick the checkbox and click Go to sign in to DSM UC.
For more information on setting up UC3200, please refer to the Hardware Installation Guideavailable at Synology's Download Center. After signing in to DSM UC, click the upper-left Main
Menu icon to see the built-in applications and start configuring your UC3200.
In this administrator's guide, the second chapter offers an overview of the key features,
advantages, and common scenarios of UC3200; the third chapter demonstrates the methods
for optimal UC3200 deployment; the fourth chapter guides you through UC3200 deployment
after you receive a new controller or an entire UC3200 through the return merchandise
authorization (RMA) service; and the fifth chapter concludes this guide and offers links torelevant resources.

2 If both Controller A and Controller B are powered off, pressing the power on button will simultaneously power on both controllers; however, if Controller A is already powered on,pressing the button will only power on Controller B.
3 Synology Unified Controller must be connected to the Internet to install DSM UC with Web Assistant. Chrome and Firefox are the suggested browsers.
4 All the connected network interfaces will be displayed here. For example, if LAN1 on both controllers are connected, then two IP addresses will be listed. You may choose either IP
address to sign in.

02

Quick Start

Quick Start

This chapter provides an overview of UC3200's major features and relevant settings. For stepby-step instructions on feature management and settings, please refer to the Help articles.

Manage Users
In Control Panel > User, the flexible user management options allow you to create andmanage administrator user accounts. Please note that only administrator users can be createdon UC3200.
• Go to the User tab to create, edit, remove, or import administrator users.
• Go to the Advanced tab to configure password setting rules and the password expiration
schedule, thereby adding an extra layer of protection to user accounts.

03Quick Start

Modify Network Settings
In Control Panel > Network, you can configure network settings to connect your UC3200 to
the network, aggregate network interfaces, enable the failover feature, and more. Here we'll
guide you through some of the key configurations for ensuring data security and network
stability.

Set Static IP Addresses
IP addresses are assigned automatically (DHCP) by default during the initial setup. An
IP address may possibly change under certain circumstances such as system reboots;
therefore, we highly recommend configuring static IP addresses before proceeding with otherconfigurations.
In fact, IP addresses must be set static first if you want to enable the network failover feature(see the Enable Network Failover section for details). To set a static IP address, please
complete the following steps:
1. Go to Control Panel > Network > Network Interface and select a LAN that you want to
set a static IP address. Click Edit.
2. Select IPv4 or IPv6 and select Use manual configuration.
3. Enter the IP address and other information, and click OK to finish.

Manage Link Aggregation
Link Aggregation increases the redundancy or bandwidth of your UC3200 by aggregating
multiple network interfaces, and provides traffic redundancy to maintain network connection
in case connection is down. To combine multiple LANs, please complete the following steps:
1. Go to Control Panel > Network > Network Interface.
2. Click Create > Create Bond.
3. Select a controller and click Next. Follow the on-screen instructions to finish.

04

Quick Start

After the LAN interfaces are combined, a new interface named Bond will appear
in the Network Interface tab.

Enable Network Failover
Network failover is designed to ensure service continuity. Enabling this feature on a LAN port
ensures that if a controller breaks down, its tasks and IP addresses will be automatically takenover by and switched to the other controller. Since this feature can only be enabled on LAN
ports with static IP addresses, please make sure your IP addresses are set static first.
Once network failover has been enabled and a LAN port has been specified, the port will beprotected in the event of network failure or controller malfunctioning. For example, if network
failover is enabled on LAN 1 and if Controller A unfortunately breaks down due to hardware
issues, network issues, or other unexpected events, then all the incoming connections directed
to LAN 1 of Controller A will be re-directed to LAN 1 of Controller B. This ensures service
continuity and almost zero downtime.
If you want to perform specific tasks on a certain controller, we do not recommend enabling
network failover on a LAN port because an IP address may be assigned to different controllers
when this feature is enabled, thus possibly preventing a controller from being identified
through its IP address. For example, this feature should not be enabled on a LAN port under
the following circumstances:• If you want to always connect to a controller via a LAN port.
• If you want to retrieve system information via the SNMP protocol.
Before enabling network failover, please make sure the LAN port is connected, the static IP
address is set, and the subnet is under the same network environment. Afterward, please
complete the following steps:
1. Go to Control Panel > Network > General.
2. Go to the Network Failover section and click Set Interface for Network Failover.
3. Select the preferred network interfaces (only the interface in Normal status can beselected) and click OK.

Deploy Storage Space
Before the various UC3200 features can be fully managed, you must create at least one
storage pool and one volume in Storage Manager. This application is designed for deploying
storage spaces, simplifying storage management, and creating flexible storage spaces withdata protection, thereby helping you accomplish the following tasks and more:• Create storage pools and volumes• Monitor and assign the installed drives• Improve SSD performance• View the health status and connection status05

Quick Start

Create Storage Pools and Volumes
Storage pools are storage capacity aggregated by multiple drives, and can be configured invarying sizes to enhance storage performance, management, and data protection. Volumes
provide the basic storage space on your UC3200. All data are stored on volumes, and volumes
are created on storage pools. Therefore, a storage pool must be created before a volume canbe created. UC3200 supports the Btrfs file system.
To create a storage pool and volume, please go to the Storage Pool and Volume pages
respectively and click Create.5 A controller must be selected for storage pool creation, and a
RAID type must be selected for data protection.6 After a storage pool has been created, you
can go to Storage Pool > Action > Change Controller to change and mount the storage poolon another controller, thereby balancing the CPU usage of the two controllers.

Monitor and Assign the Installed Drives
In the HDD/SSD page, you can monitor drive performance and health status, enable write
cache support to enhance system performance, optimize read/write performance of volumes,
and more.7
In the Hot Spare page, you can assign the standby drives as hot spare drives, which willautomatically replace the defective drives in a degraded storage pool on UC3200 or its
connected expansion units (i.e., RXD1219sas). To replace the defective drives, the hot spare
drives must be installed in the same chassis as where the defective drives are located. Standby
drives can be assigned as hot spare drives once the following criteria are met:
• The RAID type of the storage pool supports data protection.8• The size of the hot spare drive must be equal to or larger than the size of the smallest drivein the storage pool.

Improve SSD Performance
In an all-flash volume, we recommend enabling SSD TRIM, which improves the read and write
performance of the volumes created on SSDs. To enable SSD TRIM, please go to the Volume
page and select a volume that consists entirely of SSDs, and then click Action > Configure andfollow the wizard to complete.
In the SSD Cache tab, you can mount an SSD cache to a volume to improve the performanceof Random Access. Please note that an SSD cache and its corresponding volume must be
created on drives in the same chassis. UC3200 supports two SSD cache types, namely, readonly cache and read-write cache.9

5 Before you create a storage pool, make sure there is no important data on the drives on which the storage pool will be created. All existing data will be deleted during the creation
process.
6 Please refer to here for the supported RAID types.
7 The drives installed in UC3200 cannot be migrated to Synology NAS.
8 SHR, RAID 1, RAID 5, RAID 6, RAID 10, and RAID F1 are the RAID types that support data protection.
9 Please make sure your data are properly backed up because there is a high risk of data loss if the volume on which an SSD read-write cache is mounted crashes.

06

Quick Start

View Health Status and Connection Status
After the configurations are done, you can go to the Overview page to view the health status
of volumes, storage pools, and drives, and take corresponding actions whenever an issue
occurs. You can also go to the Expansion page to see the connection status between yourUC3200 and the connected expansion units.10

10 The graphic shown in this page merely depicts the physical condition of the UC3200 and the connected expansion units. It, however, does not reflect the scenario when one
controller breaks down and the other controller takes over the task.

07

Quick Start

Manage iSCSI Services
iSCSI Manager is designed for managing and monitoring iSCSI services, and creating iSCSI
LUNs with thick and thin provisioning.11 It supports mapping iSCSI LUNs to iSCSI targets,thereby allowing client servers to access storage spaces via their iSCSI initiators as if the spaces
were local drives.

Create iSCSI LUNs
An iSCSI LUN represents an individually addressable portion of an iSCSI Target, and can bemapped to multiple iSCSI Targets for storage operations. An iSCSI LUN is created with thickprovisioning by default, ensuring the system to provide consistent performance. The creation
time depends on the LUN size. For example, creating a 1TB LUN on a storage pool that isaggregated by HDDs and is in RAID 5 configuration may take more than 30 minutes. For users
demanding less latency and higher performance consistency, we recommend selecting thickprovisioning for LUN creation.
After a volume has been created in Storage Manager, please complete the following steps tocreate an iSCSI LUN:
1. Go to iSCSI Manager > LUN and click Create.
2. Enter the iSCSI LUN properties and click Next.
3. Follow the wizard to complete.

11 Both thick provisioning and thin provisioning are types of storage pre-allocation. With thick provisioning, the total storage capacity of a virtual drive is pre-allocated on the physicalstorage when the virtual drive is created. The drive consumes all the space allocated to it in the data store right from the start; therefore, the space is unavailable for use by othervirtual machines. Contrarily, a thin-provisioned virtual drive consumes only the space that it needs initially, and may consume more space depending on future needs.

08Quick Start

Configure iSCSI Targets
An iSCSI target is a storage resource located on an iSCSI LUN, and UC3200 supports creating
multiple targets for mapping LUNs.
Register iSCSI targets with an iSNS server
An iSNS (Internet Storage Name Service) server provides a mechanism for centralized
management. You can register all the iSCSI targets with an iSNS server if you have this server.
To enable an iSNS server, please complete the following steps:
1. In the Settings page, go to the iSNS (Internet Storage Name Service) section and tickEnable iSNS.
2. Enter the IP address or domain name of the iSNS server, and click Apply.
Set I/O queue depth for iSCSI targets
I/O queue depth determines the maximum number of iSCSI commands that can be sent to thequeue during each iSCSI session. A longer queue depth may help enhance throughput in
10/40 GbE network and SSD environments; a shorter queue depth may help address latency orstability issues. I/O queue depth of all targets can be modified by completing the steps below:
1. In the Settings page, go to the I/O Queue Depth section.
2. Click the I/O drop-down menu and select the preferred value, and click Apply. For therecommended value, please refer to the Set I/O Queue Depth section.

Protect iSCSI LUNs with Snapshots
A snapshot of an iSCSI LUN is a point-in-time and read-only copy of an iSCSI LUN, aimed forincreasing the level of data protection. The snapshot feature is also available in Snapshot
Replication. Please refer to the Take snapshots for an iSCSI LUN section for more
information.

09

Quick Start

Back Up and Recover Data
Snapshot Replication is a data backup and recovery solution providing schedulable and nearinstantaneous data protection. It ensures that corporate data and virtual machines in iSCSI
LUNs remain safe and available in the event of accidental deletion, application crash, data
corruption, or other unexpected events.

This application helps you accomplish the following tasks:• Take and manage snapshots of iSCSI LUNs
• Configure scheduled snapshots and retention settings• Create and manage replication tasks for iSCSI LUNs
• Configure scheduled replication to periodically sync replication tasks• Restore data from snapshots, and perform failover/switchover of replication tasks between
the source and destination• View the event logs related to snapshots and replications
UC3200 also supports creating snapshot schedules and replicating data to another UC3200 or
Synology NAS running on DSM 6.2.2 or versions above.

Take snapshots for an iSCSI LUN
The "snapshot" feature is a point-in-time copy of the data being taken. Only thin-provisioning
LUNs support taking snapshots, and up to 4,096 snapshots can be taken for LUN protection.
Snapshots take up only a small amount of additional storage space, and do not affect system
performance. In short, data that are accidentally modified or deleted from a volume can beinstantly restored back to the previous time at which the snapshot was taken. To create asnapshot, please complete the following steps:

10Quick Start

1. Go to the Snapshots page and select the iSCSI LUN that you want to take a snapshot.
2. Click Snapshots > Take a Snapshot.
3. Enter the description and tick or untick the Lock checkbox to determine whether to ignore
the retention settings when automatic removal is triggered.
4. Click OK to start taking a snapshot.

Create replication tasks for an iSCSI LUN
The "Replication" feature is a mechanism that syncs the iSCSI LUNs snapshots between thesource and destination. The replicated snapshots can even be used for performing failoverand protecting data if the replication source unfortunately fails. This feature allows you tomanage replication tasks, run or stop the syncing, and view information of the replication
tasks. To create a replication task, please complete the following steps:
1. In the Replication page, click Create and select the location and network type for thedestination.
2. Click Next and follow the wizard to finish.

Recover iSCSI LUNs
The "Recovery" feature allows recovering data from local snapshots, and restoring the entire
iSCSI LUN to the previous point-in-time.12
Restore an iSCSI LUN
If data were deleted accidentally or if you need to restore your data to the previous version,please do the following to restore the data:
1. Select the iSCSI LUN you want to restore and click Recover.
2. Select the snapshot version you want to restore from, click Action, and select Restore inplace from the drop-down list.
3. A confirmation message will appear. Click Yes to confirm the action.
Re-protect a replication task
When a replication task is failed over from the source server (i.e., UC3200) to the destination
server (i.e., another UC3200 or Synology NAS), the destination server will act as the new source
server and the task will stop syncing data between the two servers. Therefore, you will need to
re-protect the task to determine which server should act as the source server once the original
source server is recovered. Please complete the following steps to re-protect a task:
1. Select the failed over iSCSI LUN you want to re-protect, and click Action > Re-protect.
2. Select the new source, and select the new destination if there are multiple replication tasksof the iSCSI LUN.

12 To ensure that iSCSI LUNs can be fully protected, we highly recommend installing the same version of Snapshot Replication on both the source server and destination server.

11

Quick Start

3. Select to re-protect the data on either the source or destination.
4. Tick the Sync immediately after operation checkbox if you want to sync immediately.
5. Click Re-protect to start the action.
Clone a snapshot to a new iSCSI LUN
If you want to clone a snapshot to a new iSCSI LUN, please complete the following steps:
1. Select the iSCSI LUN you want to clone and click Recover.
2. Select the snapshot version you want to clone to a new iSCSI LUN, click Action, and selectClone with a new name from the drop-down list.
3. You will be redirected to the Clone page in iSCSI Manager. Enter the name of the cloned
iSCSI LUN and click OK to finish.
To ensure successful recovery of services, applications, and iSCSI LUNs, you can perform Test
Failover to clone a writable iSCSI LUN on the destination (as the simulated new source) tocheck whether the cloning works well. Performing failover regularly allows IT administrators tofacilitate punctual responses to actual situations when unexpected events occur.

Monitor Overall System Status
High Availability Manager provides a comprehensive overview of the system information,offering a quick glance at the system and health status of both controllers. It reflects real-timesystem status and alerts you when system errors occur. The following pages are offered on
the left panel:• Overview: This page displays the system and controller statuses, shows the system errors,
and offers the recommended actions.
• Controller: This page lists the detailed hardware information of both controllers.
• Performance: This page offers close monitoring of system resource usage (e.g., CPU,
memory, and volume).
• Task Manager: This page lists the ongoing processes and tasks to instantly identify system
resource distribution.
• Performance Alarm: This page offers a customizable warning level for critical services.

12Quick Start

The Overview page lists the overall system statuses (see Table 1) and displays the warning or
critical messages that may appear when an error occurs (see Table 2). A message that appears
will be followed by cluster details and recommended actions.

System Status
NormalDescription
The overall condition of UC3200 is healthy. Both internal communication andexterior services are functioning properly.
UC3200 is busy due to certain system processes. Therefore, we highly

Processing

recommend that all operations be performed after the system process iscomplete.
UC3200 has encountered minor issues. The status of the cluster is abnormal,

Warningbut the services are still functioning. Performing corresponding actions before
the issues deteriorate is highly recommended.
At least one controller has encountered major issues and its services have

Criticalmalfunctioned. Under this condition, the controller in normal operation willtake over all services. Following the given instructions to recover the cluster
immediately is highly recommended.

Table 1: Overall system status13

Quick Start

Warning / Critical Message

Description
A controller is unable to provide services, and the other controller
is taking over all services, volumes, and failover-enabled network

Service switchoverinterfaces, thereby ensuring service continuity. We highly
recommend following the on-screen troubleshooting instructions
to prevent further errors.
Some monitored network interfaces on a controller are
disconnected, and the other controller will take over those

Network interface failover

IP addresses until the interfaces are reconnected. Under thiscondition, all services going through the failover IP addresses will
not be interrupted. We highly recommend following theon-screen troubleshooting instructions to prevent further errors.
Switchover is not available due to some internal errors. This issue
is usually caused by inconsistent system or hardware settings.

Unable to switchover

It is also possible that the entire system is processing criticaloperations. We recommend following the instructions in the

Overview page to repair the system.
Firmware versions of the two controllers are inconsistent. The
system may encounter unexpected errors if the controllers
Inconsistent firmware
versioncontinue to operate in different versions. We recommend
following the instructions in the Overview page to repair thesystem. Please note that the service will be unavailable during therepair process.
The monitored items (e.g., network, service, or storage space)

Error on monitored items

have failed. We recommend following the instructions in the

Overview page to repair the system.
Heartbeat problems have been detected. Heartbeat is responsible
Heartbeat malfunction

for the communication between the two controllers. When
this issue occurs, please contact Synology Technical Support
immediately for further assistance.
One controller cannot be detected by the other controller. Under

Controller undetectable

this condition, the system is not protected by High Availability
Manager.
User setting of the two controllers is inconsistent. Please go to theInconsistent configuration

Overview page and reboot the suggested controller to resolve
this issue.

Table 2: Warning or critical messages

14

Quick Start

The Overview page also displays the following types of information:

Controller Information
This section graphically displays the basic information of the controllers, allowing you to easily
identify which part of UC3200 is malfunctioning and take corresponding actions. The graphic
displays the following information:• Controller: A controller will be highlighted if an error occurs to the controller.
• Storage Space: Drives in abnormal status will be highlighted if an error exists in thecorresponding space. Only the drives installed in UC3200 will be visually displayed if errors
occurred; that is, the drives installed in an expansion unit will not be displayed here if errors
occurred.
• Network: A network interface will be highlighted if the corresponding monitored interface isdisconnected. When this happens, the graphic of UC3200 will turn to its rear to highlight thecorresponding area.
• Power: A power supply will be highlighted if the corresponding power supply is abnormal.
When this happens, the graphic of UC3200 will turn to its rear to highlight the correspondingarea.
• Heartbeat Communication: The communication condition between the controllers isshown here.

Host Utilization
This section allows you to monitor the important resource usage of the two controllers. Pleaserefer to the following for more information:• CPU Utilization and CPU Load Average: We highly recommend keeping the CPU utilization
below 80%, so as to ensure the system can reserve sufficient resource for cluster monitoring.
When managing the CPU resource, we highly recommend reserving CPU resource in advancein case one controller needs to take over all services from the other controller duringcontroller failure.
• Memory: This indicates how much memory has been occupied. We highly recommend
always reserving 20% of the memory for system-related monitoring.
• Disk Activity: This indicates whether the drives are running data read/write activities.

Recent Important Events
The most recent five logs will be listed in this section, allowing you to understand the recent
cluster activity information (date, time, user, and event detail) at a glance. You can also
instantly trace the most recent activities in the cluster when issues occur to the system. For
complete log records, please refer to Log Center.

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Optimal UC3200 Deployment

Optimal UC3200 Deployment

This chapter demonstrates the configurations for optimal UC3200 deployment regarding
storage space, network configuration, and iSCSI LUN and targets. Actual configurations canbe adjusted according to your environment. The recommended hardware requirements areshown below:
Recommended client server:• Installed with a 10 GbE network card
• Installed with either of the following operating systems:• Windows Server 2016 or versions above, along with the installation of Windows MPIO
• VMware 6.0 or versions above• Red Hat Enterprise Linux 7 or versions above, along with the installation of Linux Multipath
Highly-recommended drive deployment for UC3200:• Install all SSDs to create at least two volumes and accelerate the system performance

UC3200 Deployment
Create Storage Pools and Volumes
When creating a storage pool, please select a controller for managing the storage pool. The
active-active controller design of UC3200 ensures that both controllers process resources
simultaneously. To balance resource usage and ensure optimal performance of the twocontrollers, we recommend assigning different controllers for storage pool management if you
want to create at least two storage pools; that is, at least one storage pool should be createdon both Controller A and Controller B. Afterward, create at least one volume on each storage
pool.
Please follow the steps below:
1. Go to Storage Manager > Storage Pool > Create.
2. Select Better performance to ensure that the storage pool provides better performance.
Click Next.
3. From the drives that are installed in UC3200, select RAID F1 or RAID 5 configurationaccording to your needs.
• For deployment with all SSDs: Create two RAID F1 storage pools with SSDs and assign

16

Optimal UC3200 Deployment

a storage pool to each controller.
• For deployment with HDDs and SSDs: Create two RAID 5 storage pools with HDDs; andcreate and assign an SSD read-write cache to each storage pool.

Configure Network
Please refer to the following to configure your network settings:• Network failover (IP failover): When a controller malfunctions, UC3200 will switch its IP
address to the corresponding network interface on another controller. Please see the Enable
Network Failover section for more information.
• MTU value: We recommend setting the MTU value of a 10 GbE network card to 9000 toenhance the transfer speed. Please also set the MTU value of the connected devices andinitiator to 9000 to ensure that they can operate properly. To set the MTU value, please
complete the following steps:
1. Go to Control Panel > Network > Network Interface.
2. Select a LAN of a controller and click Edit.
3. Go to the IPv4 or IPv6 tab and tick Set MTU value manually. Select 9000 from the dropdown menu in the MTU value field.
4. Click OK to finish.

Deploy iSCSI LUN
When creating an iSCSI LUN, we recommend selecting thick provisioning because it offers
more stabilized performance and less latency. To do so, go to iSCSI Manager > LUN > Createand select Thick Provisioning (better performance). Follow the wizard to complete or referto the Manage iSCSI Services section for more information.

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Optimal UC3200 Deployment

Deployment for best performance (multiple LUN creation)
To fully exercise the mechanism of the active-active controller design, we highly recommend
creating at least one LUN on each controller, thereby balancing system resources and ensuring
optimal system resource usage. For example, creating a LUN on both Controller A andController B indicate that system resources are balanced between the two controllers. This
deployment guarantees better system performance because each controller only processes
50% of the system resources. If Controller A unfortunately fails, 50% of the resources under
its process will be failed over to Controller B, which will immediately take over the task andprocess 100% of the resources.
Another benefit of this deployment is that the two controllers can balance the sudden system
resource burst that may occur from time to time. In short, creating at least one LUN on eachcontroller balances system resources and ensures that both controllers can work actively andsimultaneously, thereby optimizing the performance.
Deployment for easy management (single volume creation)
The aforementioned and recommended deployment method may, however, not always be
the best practice for all environments. To be specific, creating at least one volume on eachcontroller means that storage space must be pre-allocated and reserved for each controller.
Some users may only want to create one volume on a controller for high-availability purpose
or easy management, and may therefore prefer to create one or multiple LUNs on a volume,
store all data all on that volume, and expand the volume capacity only when needed. Under
this deployment, only one controller will be activated at a time, while the other controller
remains idle. Consequently, if Controller A unfortunately fails, 100% of the system resources
will be failed over to Controller B.
Even though creating a volume on only one controller or on both controllers does not affectthe failover mechanism, the performance is, however, affected. To be specific, creating a
volume only on Controller A cannot fully exert the mechanism of the active-active controller
design because Controller A will process 100% of the system resources, without Controller
B balancing the workload. Since the resources are processed only by Controller A, theperformance will be lowered when compared with the deployment where the resources arebalanced between the two controllers.

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Optimal UC3200 Deployment

Configure Advanced LUN Settings
The Direct read/write mode delivers better performance for an all-flash storage pool,
allowing data to be randomly accessed. The Buffered read/write mode delivers better
performance when data are sequentially accessed on an iSCSI LUN. After a LUN is created, werecommend selecting the direct read/write mode for randomized I/O pattern. To do so, go to
iSCSI Manager > LUN > Edit > Advanced and select Direct read/write.

Set I/O Queue Depth
I/O queue depth determines the maximum number of iSCSI commands that can be sent to thequeue during each iSCSI session. A short I/O queue depth provides lower latency, and a longqueue depth improves the overall throughput. In fact, a longer queue depth may enhance
the throughput in a 10/40 GbE network and SSD environment. Therefore, we recommend
adjusting the I/O queue depth to 128 if your UC3200 is installed with SSD caches or SSDs anda 10 GbE network card. To do so, please go to iSCSI Manager > Settings > I/O Queue Depthand select 128 from the I/O drop-down menu.

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Optimal UC3200 Deployment

Initiator Deployment
Actual initiator settings may differ according to an initiator's architecture, such as the initiatorsdeveloped by Microsoft, VMware, or Citrix. However, we highly recommend following the MTU
value and multipath I/O settings shown below to ensure optimal initiator deployment.

MTU Value
We recommend setting the MTU value of a 10 GbE network card as the same as the MTU
value on your UC3200 to enhance the transfer speed. Please also set the MTU value of theconnected devices and initiator as the same as the MTU value of your UC3200 to ensure thatthey can operate properly. For more information on setting the MTU value, please refer to the
Configure Network section or the initiator's website.

Multipath I/O
The server connects to the IP addresses of the two controllers simultaneously to offer
multipath I/O, thereby enhancing service reliability. More stabilized performance can beachieved when the initiator correctly recognizes the Asymmetric Logical Unit Access (ALUA).
Therefore, we recommend connecting the initiator from the IP addresses of the two controllers
to iSCSI Target simultaneously to enable multipath I/O.
If the performance is not as optimal as is expected, it may be because the initiator lacks thecorresponding multipath package or its multipath policy does not prioritize performance.
Under this circumstance, please refer to the relevant information on the initiator and adjust
the multipath policy. Once you have identified which controller the LUN is created on, you cansimply connect to the iSCSI Target via the IP address of the controller, thereby ensuring the I/O
is routed through optimal paths.

20

UC3200 Deployment after the RMA

UC3200 Deployment after the RMA
If hardware malfunction unfortunately occurs to your UC3200, please sign in to your Synology
Account to submit a technical support ticket. Synology Technical Support will assist you introubleshooting the possible issues and may recommend applying for the return merchandise
authorization (RMA) service if your product or certain product parts are defective and needreplacement.13
In general, the Technical Support team will recommend applying for the RMA to either request for
the replacement of a single controller or the entire UC3200. You should receive a new controller
or a new UC3200 shortly after you follow the Technical Support team’s instructions and send thedefective product part or product back to Synology.14
Here we’ll guide you through how to deploy your UC3200 after you receive a new controller or a
new UC3200. Please refer to the following according to your condition.

If a controller is replaced through the RMA
Here we assume that one of the controllers is still working properly and can be powered on.
Please follow the steps below after you have received a new controller:
1. Insert the new controller in your UC3200 and power on your UC3200.
2. UC3200 will repair the system automatically and synchronize the configurations on the oldcontroller to the new controller automatically.
3. Once the synchronization process is complete, launch High Availability Manager and go to
the Overview page to check if any errors or corresponding suggestions are shown here. Pleasetake corrective actions when necessary.
4. Now you can continue using your UC3200 like before, without needing to adjust any
configurations.

If the entire UC3200 is replaced through the RMA
Here we assume that the drives installed in the new UC3200 are the same as those installed in theprevious and defective UC3200. Please follow the instructions below to deploy and restore someof the most important configurations on the new UC3200:

13 You can apply for the RMA only if your product is still within its warranty period and was purchased from a Synology-authorized local distributor or reseller. UC3200 is backed up by
Synology’s 5-year limited warranty. Please refer to Synology Inc. Limited Product Warranty for more information on Synology’s product warranty.
14 Before sending your UC3200 back to Synology, please click the Back up configuration button (at Control Panel > Update & Restore > Configuration Backup) to back up
the following system configurations: user, personal, password, password expiration, HTTP connection, notification, security, terminal, auto block, allow list, block list, SNMP,
performance alarm, and general iSCSI Manager settings. Please note that the backed up settings do not include Snapshot Replication or iSCSI Target settings.

21

UC3200 Deployment after the RMA

1. Install the original drives in the drive slots of your new UC3200 according to their previous order inthe old UC3200.
2. Power on your UC3200 and follow the initial set up wizard to sign in to your DSM UC (refer to Get
Started with UC3200 for more information).
3. On your DSM UC, go to Control Panel > Update & Restore > Configuration Backup > Restore
configuration to restore the system configurations that you have previously backed up.
4. Go to Control Panel > Network and complete the following to configure your network:a. Set static IP addresses for all the required network interfaces (refer to Set Static IP Addresses
for details)
b. Combine multiple LANs into Link Aggregation if needed (refer to Manage Link Aggregation for
details)c. Enable Network Failover (refer to Enable Network Failover for details)
Because the previously backed up system configurations do not include iSCSI Target or Snapshot
Replication settings, it is necessary to follow the instructions below to restore or configure thesesettings once you have completed the aforementioned steps.

To manually restore an iSCSI target
Since the iSCSI target originally mapped to an existing iSCSI LUN is lost after UC3200 replacement,
you'll need to restore the iSCSI target and map it to an iSCSI LUN again. Please follow the steps below:
1. Launch iSCSI Manager and go to the Target page.
2. Click Create and enter the target name and tick the IQN options if needed. Click Next.
3. Select Map existing iSCSI LUNs and select the iSCSI LUN you want to map to. Click Next.
4. Confirm the settings and click Apply.

To protect a thin-provisioned iSCSI LUN with snapshots
For basic iSCSI LUN protection
An iSCSI LUN created with thin provisioning can be protected by snapshots. Please refer to Takesnapshots for an iSCSI LUN for more information and follow the steps below:
1. Launch Snapshot Replication and go to the Snapshots page.
2. Select a thin-provisioned iSCSI LUN and click Snapshot > Take a Snapshot. Click OK to finish.
3. Click Settings > Schedule to schedule the snapshot. Click OK to finish.
For advanced iSCSI LUN protectioniSCSI LUN snapshots can be replicated to another destination (i.e., another Synology NAS or UC3200)
for advanced data protection. Please refer to Create replication tasks for an iSCSI LUN for more
information and follow the steps below:
1. Launch Snapshot Replication and go to the Replication page.
2. Click Create, select the destination, and follow the wizard to finish.

22Conclusion

Conclusion

The previous chapters have offered an overview of the key features, advantages, andcommon scenarios of UC3200; and have guided you through the methods for optimal
UC3200 deployment. However, this administrator's guide only touches on a portion of thepowerful features offered by UC3200. Please refer to the UC3200 Datasheet and Hardware
Installation Guide at Download Center for more information on its specifications andhardware setup, and refer to Knowledge Base for more information on the UC3200 features.
Visit our website at www.synology.com or contact us for product inquiries, technical support,
or other assistance.

23

Conclusion

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