The DS210+ is one of the two top-end dual-disk NASes that Synology offers for the 2010 model year but it must be noted that Sinology’s products vary but little in terms of firmware features. The difference is limited to special hardware traits like eSATA ports, WOL support or overall platform performance (it affects the max number of users and IP cameras). Thus, most of the description below refers to any Synology NAS with firmware version 2.3.
Hard disk drives are the main component of any NAS as they provide the storage space for user’s files. Multi-disk NASes allow to create several independent disk volumes. The firmware we are discussing supports RAID arrays of the following types: Basic, JBOD, 0, 1, 10, 5 and 6 (dual-disk NASes support only the first four variants, of course). Besides, you can use the exclusive Synology Hybrid RAID (SHR) technology which is meant for inexperienced users who want to build a RAID out of different-capacity disks and add them one after another. If there are more than one HDD, the SHR technology builds a fault-tolerant array that will survive a failure of one disk. We have seen analogous technologies in NASes from other brands.
The user can select the type of RAID he wants to use. Besides the above-mentioned RAID levels, the NAS supports iSCSI volumes in two variants. One works on the level of files: a file with a disk image is created on the specified existing disk volume. And another works on the level of data blocks and requires a separate disk volume (created automatically). The latter iSCSI variant is faster.
Synology NASes have always offered rich options for disk migration without losing data. For example, a single-disk volume can be transformed into a mirror or RAID5 (in multi-disk NASes), or you can increase the total storage capacity by replacing disks in a fault-tolerant array one after another. You can even take disks with data from one model and install them into another. This migration support is a convenient feature in many situations.
As for nonstandard situations, when a disk fails (this didn’t happen to us during our tests, though), you just replace it with a healthy one and synchronize data. If your NAS contains four disks, you can create a RAID5 array with a replacement disk which is used automatically to repair the array in case of problems.
The NAS can view the S.M.A.R.T. data of the installed HDDs and run related tests. You can check out the temperature of the HDDs on the status page. The second HDD is usually somewhat hotter than the first one due to the design of the case.
Data access is provided by means of all popular protocols including SMB/CIFS, AFP, NFS, FTP, and HTTP. To integrate into a Windows network, you choose a workgroup or a domain. The NAS can serve as a master browser (this may help if you don’t always see all devices in the network environment) and supports a recycle bin for deleted files. As for Mac OS X, you can choose a shared folder to be used with the OS-integrated Time Machine utility. Bonjour and UPnP are supported for identification purposes.
NFS doesn’t have any special settings. The two most popular applications of this protocol are to connect to Linux systems and to network media players.
The FTP server has a number of options that make it a very handy implementation. Particularly, you can change all ports (also for the passive mode), limit the speed and number of connections, enable encryption, and choose a code page.
HTTP-based access is called File Station. It allows working with data stored on the NAS via an ordinary web-browser. We will discuss File Station in more detail shortly.
The access control system is based on users with passwords that can be united into user groups. You can assign disk quotas, prohibit to change the password, and limit the account lifetime. You can also create a large number of users by importing a text file with names and passwords. Exporting is not available, though. The max number of users and groups in the DS210+ is 248 and 256, respectively (you can check out the numbers for other models at the manufacturer’s website).
Next you must specify access rights for each shared folder as no access, read only, read & write. There are special options for FTP and File Station: you can prohibit to view the list of files and to modify or download them. The accessible host or network addresses and the access type (read only or read & write) are specified for NFS.
The NAS supports up to 256 shared folders each of which can be encrypted using AES. For more security, you have to enter the encryption key each time the NAS is rebooted. The key can also be stored on the NAS so that the folder could be mounted automatically. Such encrypted folders won’t be accessible via NFS.
And interesting feature of the access control system is that you can individually restrict user access to the NAS’s services: FTP, File Station, Audio Station, Download Station and Surveillance Station. You cannot disable SMB/CIFS access in general but you can do that for each individual folder.
The NAS is equipped with a Gigabit Ethernet port. The IP address can be acquired automatically or specified manually. The network interface supports Jumbo Frames up to 9000 bytes. Senior NAS models from Synology may come with two Ethernet ports. Recently, the ability to connect wirelessly, via a USB dongle, has been added. The list of compatible Wi-Fi adapters is listed at the manufacturer’s website and includes 14 models (also with 802.11n) at the time of our writing this.
The NAS has integrated PPPoE and DDNS clients and can set up your home router automatically so that the NAS’s services could be accessed from the Internet. The list of compatible routers includes about 40 models. An integrated firewall is available for users who care about security or want to install the NAS on the global network. Firewall rules are specified using port numbers or service names.