One of the great advantages of a good NAS drive is its expandability. Buy a four-bay NAS unit, then even if your storage requirements are only for as much data you could fit on one or two disks, you can increase capacity later as needs demand. For Synology, that ability to grow with your data pool goes a step further with the Synology DS1511+. Nay, two steps further, because its network-attached RAID options can expand beyond the bounds of the internal disks, tripling capacity by adding up to two additional DX510 break-out boxes.
The Synology DS1511+ is a five-bay NAS, with disks slotting into the front in push-to-release caddies. The DX510 expansion box looks identical from the front, and also has five bays available for hard disks. It connects via locking eSATA ports on the back of the DS1511+.
Based on the current hard-disk maximum capacity of 3TB for a 3.5in SATA hard disk, a fully laden Synology DS1511+ with two DX510s represents a staggering 45TB of raw capacity. That ought to be enough for anyone...
Like other examples of Synology's network storage, the Synology DS1511+ is a smart and well-presented unit, if mostly finished in plastic rather than metal trim. Two 80mm fans help keep the air flowing around the internal disks. Unlike many NAS boxes, there are no USB ports on the front to jack in USB disk or USB thumbdrive and exchange data. Instead, joining the two eSATA ports, are four USB 2.0 ports behind.
For the all-important network connection there are two gigabit ethernet ports here. Besides supporting dual-link failover, such that two independent network paths can be connected to cover one link's downtime, Synology also promises link aggregation. This enables higher speed operation, combining the bandwidth of two network interfaces, although it requires a managed network switch to set up. Synology quotes read/write speeds up to around 166/198MBps when used this way over a Windows CIFS network.
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Synology DS1511+: DSM 3.2
For any good NAS installation, the hardware is only half the story. Network storage solutions need powerful software to drive them along, to juggle the manifold tasks the modern NAS often tackles beyond simple file serving.
For Synology, this takes the form of DiskStation Manager 3.2 (DSM 3.2). This features a very approachable graphical user interface, using HTML5 to closely resembles a modern desktop OS once you've logged on through a web browser. Animations and window transparency makes the environment feel more like a modern desktop Linux OS than a NAS configuration page.
Most of the options to configure a DiskStation are available from Control Panel, closely modelled on Mac OS X's System Preferences interface.
From Control Panel you can create Shared Folders, add users and manage groups of users; and select which network protocols are enabled, from the usual choices of CIFS for Windows users, AFP for Macs, and NFS for Linux and UNIX systems.
As well as a UPnP media server and iTunes server, Synology offers its own Audio/File/Download and Photo Stations. These allow network access from free iPhone and iPad apps. There's even a mail server included here. WebDAV, LDAP and SNMP are also supported. More ambitious business networks can also set up the DiskStation for iSCSI use.
See also: Group test: what's the best NAS device?
Synology DS1511+: Setup
Like most Synology NAS drives, the DS1511+ is supplied as an empty unit to which you must insert your own hard disks. Unlike some drives, such as those from QNAP, the unit is even bereft of any operating system – you must download and install this yourself, thankfully an easy operation using the Synology Assistant software for Windows and Mac. Synology only loads the Linux kernel on embedded NAND flash; the rest of the OS is installed on a small partition created on every disk after loading into the NAS.
After assembling some disks and plugging into your network, this first helps locate the unit after it's been assigned an IP address by your router's DHCP server. Synology Assistant then guides you through the process of installing the OS and setting up your chosen volume structure.
Aside from the usual JBOD, RAID 0, 1, 5 and 6 types, Synology has its own SHR (Synology Hybrid RAID) system. This allows disks of different capacities to be mixed together, without the usual limitation of reducing the final sum to a multiple of the smallest disk in the array. In fact, this is the default RAID option in DSM 3.2.
Synology DS1511+: Performance
We tested the DS1511+ over a gigabit network, using one LAN port. Networking protocol was AFP, and the disks fitted were Western Digital Caviar Green, three disks of 1TB, 1TB and 1.5TB capacity in SHR mode.
At the 1MB file size level, we saw write speeds of about 39MBps, and reads of around 93MBps.
Moving to larger files let the Synology perform stretch its legs, up to 49MBps for sequential writes and 122MBps sequential reads, using 100MB data.
As can be typical for network-attached storage, small file handling was much slower, around 2MBps for random writing of 4kB files, and 9MBps random reads.
Using Blackmagic Disk Speed Test with its largest file tests, the DS1511+ showed sustained read speeds of 88MBps and 110MBps for writes.
Power consumption of the system when idle with three disks was just 21W.