Synology makes a bold move into high availability IP SAN territory with a storage array that has uptime and value as high priorities. The UC3200 is its first appliance to boast an active/active architecture and its price tag of $5,989 for a diskless unit looks incredibly good value.
The UC3200 sports dual controllers each with quad-core 2.4GHz Intel Xeon D-1521 CPUs and 8GB of ECC DDR4 memory which can be upgraded to 64GB. The controllers communicate internally with each over a high-speed hardware NTB (non-transparent bridge) where they perform fast syncing of cached data to provide transparent failover.
This makes the UC3200 ideal for budget-conscious SMBs and mid-range companies that can’t afford any storage service downtime. Should a controller fail or need to be removed, the UC3200 will automatically switch all operations to the remaining controller without any service interruptions.
The controllers each present a 10GBase-T and two Gigabit ports and networking can be expanded with their integral PCI-Express slots. Synology has currently certified its own single and dual-port 10GbE cards plus 25GbE adapters from Intel and Marvell.
UC3200 Easy deployment
The DSM HAM apps keeps you posted on controller issues and provides transparent failover services
The UC3200 presents 12 hot-swap drive bays and supports SAS3 HDDs and SSDs where the latter can be used to provide performance-oriented storage pools or high-speed read/write caches for the HDDs. The controllers also offer external SAS3 expansion ports where you can add up to two 12-bay RXD1219sas disk shelves.
Deployment is undemanding and we installed eight 6TB Toshiba Enterprise SAS3 HDDs plus four 400GB Seagate Nytro SAS3 SSDs in the solid metal drive carriers. We then used Synology’s Web Assistant to discover the UC3200 and install the latest DSM UC software.
Each controller has its own SATA DOM to run DSM effectively isolating the OS from production data and automatic updates are applied to each of them in turn to avoid any downtime. As the UC3200 is a pure IP SAN array, the only apps supported are Synology’s Control Panel, Storage Manager, High Availability Manager (HAM), iSCSI Manager, Snapshot Replication, Log Center, Resource Monitor and Support Center.
The app of most interest is the HAM as this provides a real time status display of both controllers. You can view details such as internal temperatures while the performance screen shows usage graphs for the CPU, memory, network, disks and iSCSI services.
Perfect failover
You can choose which pairs of network interfaces you want to have failover enabled on
From the Control Panel app, failover is enabled across selected port pairs on each controller and both must be in the same subnet and have the same MTU (maximum transfer unit) set. To test failover, we created a storage pool with SSD cache and a volume managed by Controller A, added a 1TB LUN and presented it over 10GbE to a host running Windows Server 2019.
After starting a continuous Iometer session on the server using the LUN, we powered down Controller A from the DSM console. As the controller had been gracefully shut down there were no audible warnings but the HAM immediately registered its loss, posted log entries and moved all operations over to Controller B.
From the server, we could see no indication that anything had happened as Iometer continued at full speed throughout the entire failover process. The only other occurrence is when management functions are moved across, you are logged out of the web console.
The failed controller will only have the ‘Remove’ LED illuminated at the back so you can safely replace it. When the controller is back in place, briefly press the power button on the left rack ear to start it up and as soon as it’s running, the HAM will transparently shift all operations back to it
UC3200 IP SAN performance
The iSCSI Manager and Snapshot Replication apps provide good data protection features
To get the best performance out of the UC3200, we recommend playing with the iSCSI queue depth settings in the iSCSI Manager app. It may not work for everyone but setting it to 128 produced the best results in our Iometer tests.
Our test host was an HPE ProLiant DL180 Gen10 rack server with dual 16-core Xeon Scalable Platinum 8153 CPUs, 64GB of DDR4, an Emulex dual-port 10GbE card and Windows Server 2019. Using a Netgear 10GbE switch to connect the server with the appliance, we created a dual 10GbE MPIO link across both controllers.
The UC3200 uses ALUA (asymmetric logical unit access) so connecting the server to both controllers provides redundancy but doesn’t double performance as the primary link is optimized with the secondary link reserved for failover. Overall performance is mixed as we recorded Iometer sequential reads and writes of 9.2Gbits/sec and 7Gbits/sec.
Changing to random operations saw read and write rates of 9.2Gbits/sec and a lowly 3.5Gbits/sec. Our I/O throughput tests bore these out as 4KB transfer requests delivered sequential read and write rates of 123,000 and 81,000 IOPS which dropped to 109,000 and 31,000 IOPS for random operations.
UC3200 Data protection features
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With no other backup apps available, you’ll be relying on DSM’s snapshot and replication services to protect your IP SANs. They are easy to use as you can run on-demand and scheduled snapshots on selected thin-provisioned LUNs using either the iSCSI Manager or Snapshot Replication apps.
Snapshots can be run as often as every five minutes and you can apply different retention policies depending on how long you wish to keep them for. Recovery is swift as you can rollback a snapshot or clone it and present a new LUN.
The Snapshot Replication app manages replicating snapshots to local volumes and remote Synology appliances. You can replicate a snapshot to as many as three separate destinations, schedule replications for regular intervals and apply retention policies.
Conclusion
With prices for most competing active/active IP SAN arrays starting at five figures, Synology’s UC3200 looks astoundingly good value. Overall performance is a mixed bag but the UC3200 receives top marks for its seamless and totally transparent failover services.
