Failover and performance
To test failover, we powered off the active controller from the HAM app whereupon it flagged up a warning message that all storage services would be interrupted while it promoted the passive controller. The process took 90 seconds and during this phase, we lost contact with all our network shares plus iSCSI LUNs and were logged out of the DSM console.
Once the controller had been promoted, everything sprang back to life but apps such as backup will be terminated if the active controller fails. We tested this by running Iometer on a share during this process and it had to be restarted when failover had finished.
There was nothing to do when the failed controller was powered back up. It re-established contact with the new active controller, was automatically assigned the passive role and all without any further interruptions to storage services.
For 10GbE testing, we installed dual-port Emulex fibre SFP+ cards in both controllers and linked them to a Netgear 10GbE switch. With a share mapped to an HP ProLiant DL380 Gen9 server (web ID:23173), we saw Iometer report raw read and write speeds for a network share of 1,108MB/sec and 1,100MB/sec.
Real world copies of our 50GB test file also returned fast sustained read and write speeds of 412MB/sec and 400MB/sec. IP SANs are fast as well with Iometer returning raw read and write speeds for a 500GB target of 1,060MB/sec and 1,000MB/sec.
Failover worked fine but it will interrupt all storage services during this brief phase
Conclusion
The RC18015xs+ puts Synology into a whole new market and the minimum hardware of two controllers and one disk shelf is comparatively expensive. Qsan's TrioNAS LX U400HA-D424 (web ID:24575) costs around the same but offers dual active/active controllers and fast, transparent failover for NAS and IP SAN services.
That said, with Synology's DSM software at the helm, the RC18015xs+ delivers an impressive range of storage features you won't find elsewhere. Support for BTRFS volumes also provides valuable unlimited snapshots, it delivers good performance and expansion potential is huge.
Verdict
The RC18105xs+ performed well during testing and delivered very good NAS and IP SAN performance. Failover is nicely automated but it will interrupt services and for an active/passive fault tolerant solution, it isn’t the best value
2 x RC18015xs+ each with the following specification: Chassis: 1U rack CPU: 3.3GHz Intel Xeon E3-1230 v2 Memory: 8GB DDR3 (max 32GB) Network: 5 x Gigabit (4 x LAN, 1 x Heartbeat) Expansion: 1 x SAS out, 1 x PCI-Express 8X slot Array support: RAID0, 1, 10, 5, 6, hot-spare, JBOD, SHR Power: 2 x 150W hot-swap PSUs Management: Web browser Warranty: 5-year limited RXD1215sas drive shelf (max 15): Storage: 12 x SAS 6Gbps hot-swap drive bays Ports: 4 x SAS (2 x In/2 x Out) Power: 2 x 500W hot-swap PSUs Warranty: 5-year limited
