What is a NAS? NAS Stands for Network Attached Storage, and it is a device that resides on your network and can have multiple drives in a RAID array. The drives contain folders that can be accessed by all or a few computers on your network depending on the permissions set. Having a NAS on your network offers a few benefits such as increase in storage capacity, data encryption, and depending on the RAID Array, limited protection of data stored on the device. Most units offer features that go beyond just a storage device; a lot of the desktop NAS offer features such as a media library, media streaming, iTunes Server, and cloud based backups. Synology's DS1515+ is a 5-bay NAS that features an Intel Quad Core CPU, 2GB of DDR3 RAM and four gigabit Ethernet ports. Packaging Typically, a NAS is marketed towards the Small Office/Home Office (SOHO) or small business crowds so, flashy packaging isn't necessary. The same goes for the Synology DS1515+ as the packaging is plain cardboard with black text and line art graphics with a couple of informational stickers attached. Internally, the NAS is packed away in a pair of rigid foam inserts and covered with a soft anti-scratch bag. The Synology DS1515+ comes with a 6' power cord, two 6' Ethernet cables, hard drive screws, a set of keys, and a quick start guide. Specifications Hardware Specifications CPU CPU Model Intel Atom C2538 CPU Architecture 64-bit CPU Frequency Quad Core 2.4 GHz Floating Point X Hardware Encryption Engine (AES-NI) X Memory System Memory 2 GB DDR3 Memory Module Pre-installed 2 GB x 1 Total Memory Slots 2 Memory Expandable up to 6 GB (2 GB + 4 GB) Storage Drive Bay(s) 5 Maximum Drive Bays with Expansion Unit 15 Compatible Drive Type (See all supported drives) 3.5" SATA III / SATA II HDD 2.5" SATA III / SATA II HDD 2.5" SATA III / SATA II SSD Maximum Internal Raw Capacity 40 TB (8 TB HDD x 5) (Capacity may vary by RAID types) Maximum Raw Capacity with Expansion Units 120 TB (8 TB HDD x 15) (Capacity may vary by RAID types) Maximum Single Volume Size 108 TB Hot Swappable Drive X External Ports USB 3.0 Port 4 eSATA Port 2 File System Internal Drives EXT4 External Drives EXT4 EXT3 FAT NTFS HFS+ Appearance Size (Height x Width x Depth) 157 mm x 248 mm x 233 mm Weight 4.17 kg Others RJ-45 1GbE LAN Port 4 (with Link Aggregation / Failover support) Wake on LAN/WAN X System Fan 80 mm x 80 mm x 2 pcs Fan Speed Mode Cool Mode Quiet Mode Easy Replacement System Fan X Wireless Support (dongle) X Power Recovery X Noise Level* 22.3 dB(A) Scheduled Power On/Off X Power Supply Unit / Adapter 250W AC Input Power Voltage 100V to 240V AC Power Frequency 50/60 Hz, Single Phase Power Consumption* 38.39 W (Access) 21.63 W (HDD Hibernation) British Thermal Unit 130.99 BTU/hr (Access) 73.80 BTU/hr (HDD Hibernation) Environment Temperature Operating Temperature 5°C to 35°C (40°F to 95°F) Storage Temperature -20°C to 60°C (-5°F to 140°F) Relative Humidity 5% to 95% RH Certification FCC Class B CE Class B BSMI Class B Warranty 3 Years Notes Power consumption is measured when fully loaded with Western Digital 1TB WD10EFRX hard drive(s). Noise Level Testing Environment: Fully loaded with Seagate 1TB ST31000520AS hard drive(s) in idle; Two G.R.A.S. Type 40AE microphones, each set up at 1 meter away from the Synology NAS front and rear; Background noise: 16.49-17.51 dB(A); Temperature: 24.25-25.75˚C; Humidity: 58.2-61.8% DSM Specifications ( See more ) Storage Management Maximum Internal Volume Number 512 Maximum iSCSI Target Number 32 Maximum iSCSI LUN 256 iSCSI LUN Clone/Snapshot, Windows ODX X Supported RAID Type Synology Hybrid RAID Basic JBOD RAID 0 RAID 1 RAID 5 RAID 6 RAID 10 RAID Migration Basic to RAID 1 Basic to RAID 5 RAID 1 to RAID 5 RAID 5 to RAID 6 Volume Expansion with Larger HDDs Synology Hybrid RAID RAID 1 RAID 5 RAID 6 Volume Expansion by Adding a HDD Synology Hybrid RAID RAID 5 RAID 6 JBOD Global Hot Spare Supported RAID Type Synology Hybrid RAID RAID 1 RAID 5 RAID 6 RAID 10 SSD Support SSD Read/Write Cache (White Paper) X File Sharing Capacity Maximum User Accounts 2048 Maximum Groups 256 Maximum Shared Folder 512 Maximum Shared Folder Sync Tasks 8 Maximum Concurrent CIFS/AFP/FTP Connections 512 Windows Access Control List (ACL) Integration X NFS Kerberos Authentication X High Availability Manager X Log Center X Syslog Events per Second 800 Virtualization VMware vSphere 5 with VAAI X Windows Server 2012 X Windows Server 2012 R2 X Citrix Ready X Add-on Packages (See more) Antivirus Essential X Antivirus by McAfee (Trial) X Audio Station X Central Management System X Cloud Station X Maximum Concurrent File Transfers 512 Cloud Sync X Directory Server X DNS Server X Download Station X Maximum Concurrent Download Tasks 80 Glacier Backup X HiDrive Backup X iTunes Server X Java Manager X Mail Server X Mail Station X Media Server X DLNA Certification X Note Station X Photo Station X RADIUS Server X Surveillance Station X Maximum IP cam (Licenses required) 40 (including 2 Free License) (See All Supported IP Cameras) Total FPS (H.264)* 1200 FPS @ 720p (1280x720) 480 FPS @ 1080p (1920×1080) 250 FPS @ 3M (2048x1536) 200 FPS @ 5M (2591x1944) Total FPS (MJPEG)* 300 FPS @ 720p (1280x720) 150 FPS @ 1080p (1920×1080) 100 FPS @ 3M (2048x1536) 60 FPS @ 5M (2591x1944) Time Backup X Maximum Task Number 8 Video Station X Video Transcoding Group 1 - Type 1 (See more) VPN Server X Maximum Connections 20 Notes Surveillance Station throughput is tested with Axis network camera, using continuous recording with live view from Surveillance Station and motion detection by camera. Live view and recording are sharing the same stream from the camera. Environment & Packaging Environment RoHS Compliant Packaging Content Main Unit X 1 Welcome Note X 1 Accessory Pack X 1 AC Power Cord X 1 RJ-45 LAN Cable X 2 Optional Accessories Remote Camera License Pack 4GB DDR3 RAM Module Expansion Unit: DX213 X 2 Expansion Unit: DX513 X 2 VS360HD A Closer Look at the Synology DS1515+ The Synology DiskStation DS1515+ is a 5-bay NAS and measures 157(H) x 248(W) x 233(D) mm (6.2(H) x 9.8(W) x 9.17(D) inch) and weighs 4.17 kg or 9.19 lbs empty. The drive trays are removed by pushing in on the front cover of each drive bay. This will unlock the drive tray and allow it to be removed. Each drive tray can be locked with a key to prevent unauthorized removal of the drives. The LED status indicators and the power button for the Synology DS1515+ are located at the top of the unit. The drive LEDs are small triangle indicators located at the top of each of drive trays. A recessed Synology logo is prominent on both sides of the DiskStation DS1515+. All of the I/O is located on the back of the NAS. Cooling for the NAS is provided by dual 80mm fans. The fans and brackets are held into the case via two screws thus facilitating easy removal and replacement. The DS1515+ offers a good amount of connections. Featured on the back are 4 USB 3.0 ports, 4 1 gigabit Ethernet ports, and 2 eSATA ports. With the drives removed, you can see the center section of the chassis is open. This should allow good airflow across the drives when installed. The CPU in the Synology DS1515+ is the Intel Atom c2538. The CPU is a Quad-Core that runs at 2.4 GHz and is passively cooled via the silver heatsink on the front of the board. Dual SODIMM slots, one on the front and one on the back, support up to 12 GB or DDR3/DDR3L RAM at 1600 MHz. The network controller for the DS1515+ is the Marvell Alaska 88E1543 and supports 4 physical layer Ethernet ports. The Silicon Image Sil3132CNU is responsible for managing eSATA connections. From the specifications I could find online, the 3132 supports single lance PCIe and can be multiplexed into two SATA Gen 2 or SATA3 ports. This makes sense as the eSATA daughter card plus into the PCIe x1 port on the motherboard. The 4 USB 3.0 is handled by the EtronTech EJ188H controller IC. Synology DiskStation DS1515+ Start-up Wizard After installing the drives, you'll need open a browser window and go to the IP Address of the DS1515+. The first task the wizard will step though is updating your firmware. As long as the NAS has access to the internet, it will go to Synology's website and download the latest and greatest firmware. If the NAS cannot connect to the internet, a manual install option is available. The DiskStation 1515+ will show an installation progress meter while installing the firmware. After installation is complete, the NAS will reboot. After the device reboot, you will be taken to the next step of the process which, is to set the NAS's name on the network and set up an administrative username and password. The next page will ask how you would like the updates to install from Synology and when to schedule them. The next step in the setup process is to create a QuickConnect ID. QuickConnect is Synology's solution allowing users to access the data on the NAS anywhere they can get internet access without having to worry about configuring networking equipment. The final pages is the configuration confirmation page. After you click the next button, you'll be taken to the DSM desktop. DiskStation Manager (DSM) User Interface DiskStation Manager or DSM is the interface you will use to configure the NAS with; the latest released verison is 5.2 with 6.0 beta 2 available for download. There are a lot of configuration options in DSM. I am covering what I feel is the most important options in order to get the NAS up and running on the network. After the initial configuration, anytime that you'll want to log into the NAS, you'll need to enter the username and password that was set up in the Startup Wizard. After logging in, you'll be taken to the desktop. The desktop functions in a similar manner to the Windows desktop on your PC. You can create shortcuts to the most used configuration items in the menu. By default, a small monitoring application launches in the lower right side of the page. The application displays quick details on the utilization and health of the NAS. The main application on the menu that will be used to configure the NAS will be the control panel. The control panel has most of the options that will be needed to get the NAS up and running. By default a lot of the services needed, such as file services have already been turned on. After the disk volume has been created (next section) you'll just need to create shared folders and assign permissions and the users can start using the NAS. Users and groups can be created to give access to the NAS's shared files and folders. If no users are created, you will need to give the guest or public account read/write access to the shared files. If you run a Windows Active Directory domain, you can configured the NAS to synchronize user information from your domain. At that point, you will also be able to grant domain users access to shared folders and eliminates the need to create separate users for your domain and your NAS. The network menu is where all the networking configuration is done. Since the Synology DS1515+ has four network interfaces, they can be configured for load balancing as well as fail over. However, you will need a managed switch capable of creating a Link Aggregation Group (LAG) and LACP in order to do load balancing. Keep in mind that creating a LAG will not increase bandwidth from a single host. It increases the overall bandwidth the NAS can use on your network to multiple hosts. If you don't have the ability to cable your NAS for example in a dorm room, you can install a USB wireless or bluetooth adapter and get network access that way. The security tab allows you to configure such items as user interface timeouts, firewall, and certifications. The firewall tab can be used to restrict network traffic to and from the NAS in order to help protect it from network attacks and can help reduce the chance of a network breach. The NAS also offers denial-of-service protection and the ability to install your own certificate to further secure the NAS. DSM Storage Manage In order to be able to do anything other than look at the user interface with the NAS, a volume or disk group needs to be created. This will take the drives installed in the NAS and configure them based on your input. After the volume is created you will then be able to create shared folders and put data on the NAS. Storage Manager is accessed in the same way as the control panel. The overview menu gives you quick information on how many drives are in use, set as spares, and are available for expansion as well as gives the volume usage. A volume is created in the volume menu. There are two options: quick and custom. In either mode, the next step is to select which drives you want available in the volume. In Quick mode, you'll be asked if you want the fault tolerance of one disk or two. If you choose custom mode, you'll have the option to choose a singe volume on RAID or multiple volumes on RAID. With the custom volume, the next step is to choose which RAID array you'd like to create. Available RAID options (depending on the number of disks selected) are: RAID 0, RAID 1, RAID 10, RAID 5, RAID 6. After you've chosen the type of RAID array you'd like, the next page will ask to perform a bad sector check. I would say for the sake of data integrity, perform the check. Yes it will take time, but the extra time you take to make sure the drives are good now could save you a major headache later on. Finally, the last page will confirm your settings. Just click on the finish button and the DS1515+ will start creating your array. Testing Methodology System Configuration Case Cooler Master Cosmos II SE CPU Intel i7 4770K Motherboard MSI Z97m Gaming Ram 2 GB G.Skill F3-12800CL9q DDR3-1600 GPU MSI GTX 970 OC Hard Drives Samsung 840 EVO 256gb SSD Western Digital black 500 gb 7200 RPM HDD Power Supply NXZT Hale v2 1000 Watt power supply 4 Seagate 4 TB 7200 RPM desktop drives were installed and used in the NAS tests. A dual port Intel network card was installed in the test system. The Synology DiskStation DS1515+ was configured to use a Single Volume on RAID. In my testing I used the QNAP TS-451, QNAP TS-563& the Seagate DP-6 to get comparison numbers against the Synology DS1515+. The DS1515+ shipped with 2GB of RAM. The QNAP TS-563 shipped with 8 gb of RAM. All tests were performed with 4 drives. Network Layout For all tests the NAS was configured to use the a single network interface. One CAT 6 cable was connected to the Cisco 2960 from the NAS and one CAT 6 cable was connected to the workstation from the switch. Testing was done on the PC with only 1 network card active; the Killer network card and the corresponding software were disabled for the testing. The switch was cleared of any configuration and left in a unconfigured state. Jumbo frames was not enabled and no changes to the network interfaces was made. Software All testing is done based off of a single client accessing the NAS. We are currently working on a multi-client testing solution. Stay tuned. To test NAS Performance I used The Intel NAS Performance toolkit and Atto Storage benchmark. The Intel NAS Performance toolkit simulates various tasks for storage devices such as video streaming, copying files and folders to and from the NAS as well as creatingcontent directly on the NAS. To limit caching, a 2GB G.Skill memory module was used in all tests. All options in the Performance toolkit were left that the defaults. The NAS performance test is free to download. You can pick up a copy for yourself here. All tests were run a total of three times then averaged to get the final result. RAID 0, RAID 10, and RAID 5 are all tested. Tests were run after all the RAID arrays were fully synchronized RAID Information Images courtesy of Wikipedia JOBD or Just a Bunch Of Disks is exactly what the name describes. The hard drives have no actual raid functionality and are spanned at random data is written at random. RAID 0 is a stripe set and data is written across the disks evenly. The advantage of RAID 0 is speed and increased capacity. With RAID 0 there is no redundancy and data loss is very possible. RAID 1 is a mirrored set and data is mirrored from one drive to another. The advantage of RAID 1 is data redundancy as each piece of data is written to both disks. The disadvantage of RAID 1 is write speed is decreased as compared to RAID 0 due to the write operation is performed on both disks. RAID 1 capacity is that of the smallest disk. RAID 10 combines the 1st two raid levels and is a mirror of a stripe set. This allows for better speed of a RAID 0 array but the data integrity of a RAID 1 array. RAID 5 is a stripe set with parity. RAID 5 requires at least 3 disks. Data is striped across each disk, and each disk has a parity block. RAID 5 allows the loss of one drive without losing data. The advantage to RAID 5 is read speeds increase as the number of drives increase but the disadvantage is write speeds are slower as the number of drives is increased. There is overhead with RAID 5 as the parity bit needs to be calculated and with software RAID 5 there is more of a performance hit. RAID 6 expands on RAID 5 by adding an additional parity block to the array that is distributed across all the disks. Since there are two parity blocks in the array more overhead is used with a RAID 6 array. For a full breakdown of RAID levels, take a look at the Wikipedia article here. RAID configurations are a highly debated topic. RAID has been around for a very long time. Hard drives have changed, but the technology behind RAID really hasn’t. So what may have been considered ideal a few years ago may not be ideal today. If you are solely relying on multiple hard drives as a safety measure to prevent data loss, you are in for a disaster. Ideally you will use a mutli-drive array for an increase in speed and lower access times and have a backup of your data elsewhere. I have seen arrays with hot spares that had multiple drives fail and the data was gone. Do yourself a favor and read up on the different types of RAID arrays and plan accordingly. Personally, I use a RAID 10 array with an automated backup to the cloud. I feel with that setup, I’ve done what I can to keep my data safe. Intel NAS Performance Toolkit Results Synology Hybrid RAID Synology has a RAID array they call Synology Hybrid RAID (SHR). Essentially it is for those users that do not know a whole lot about RAID or those users that don't want to fuss with setting up a RAID array. There are two options available for SHR, 1-disk (similar to RAID 5) or 2-disk redundancy (similar to RAID 6). The redundant disk basically mean you can lose n number of drives (n is the number of redundant disks) and the array will continue to work and data will still be available with no corruption. SHR also allows the use of mixed size drives meaning, that all the drives in your NAS do not have to be the same capacity. You can do the same with a traditional RAID array however, all the drives in the array can only use the amount of space available on the smallest drive. For example, in a 5 drive array the smallest disk is 250 GB. You would create a 5x250 GB raid array. With SHR, the system divides the disks into smaller chunks and creates additional redundant storage. There's a catch however, you must have two of the largest drives installed. Taking the example above, with 5x250 GB drives, you could swap out 2 of the drives to 1 TB drives and be able to use all of the disk space available. Besides ease of setup, SHR also allows you to expand to larger disks on the fly, one disk at a time. I was easily able to expand a 4 drive SHR array into a 5 drive array. However, it did take about 12 hours to add a 4 tb drive to the array. SHR does suffer from a performance hit compared to traditional RAID. In the result below, I took a 4 disk SHR 1-disk redundant array and compared it against a 4 disk RAID 5 array. Conclusion and Final Thoughts A NAS offers the ability to keep your data safe, in most cases and depending on the RAID type, from a single drive failure while offloading the RAID processes to another machine on your network. A NAS affords the ability to offer up space to other users and machines on your network and not just a little storage but the ability to have 10's of Terabytes of space available. Most desktop style NAS offer more than just storage too. The ability to host media on your network and stream to multiple devices is a hot item and is available on every NAS I've reviewed over the last year. For the more advanced users, applications such as web servers, logging servers, and back up servers are also available. I feel the Synology DS1515+ hits a nice performance to price ratio out of the box. With only 2GB of RAM installed the DS1515+ was able to keep up and in quite a few cases surpass performance of some of the more expensive NAS in our tests. One of the features that folks really like is the ability to stream media to multiple devices on the network. Not all devices support all media formats so, the NAS will have to transcode them. Transcoding uses CPU cycles. The Synology DS1515+ was easily able to transcode video files via PLEX and during the process CPU utilization reached a max of 90%. Even with utilization up that high, video playback was smooth with no artifacting and no audio issues. At one point I started another video that did not need to be transcoded and it played perfectly as well. The Package Center is essentially the Synology "store" and is where you would install additional applications such as Amazon Glacier back ups, download station, media server, etc. Most are free and work well. Others may cost or require you to sign up for a subscription. Having RAID at home is a nice feature. I find that with the hobbies that I have, I need ever increasing disk space, even if it is only temporary. It is a nice tool to have on the network to be able to share out files, folders, etc. with the rest of my family with very little management. However, any form of RAID is not a data protection plan; you will still need to back up your data in some fashion. The Synology DiskStation has a apps available that will allow you to back up your data to some of the cloud service providers such as Microsoft, Amazon, and Google. If your data is important then back it up. I cannot stress that enough. I cannot tell you how many times over the last 20 or so years I've had to restore data from a failed RAID array. Overall, I really like the Synology DS1515+. I think it balances performance and features very well for a 5 bay unit. Typically with desktop NAS, the synchronization of the array can take hours. The larger the drives, the longer it takes. The Synology DS1515+ had the fastest synchronization time of any of the NAS that I've reviewed over the last year. While I didn't time all of the processes, the DS1515+ fully synchronized a RAID 5 array with four 4 TB drives in less than three hours. The DS1515+ has the ability to expand beyond the 5 bays via eSATA and Synology expansion units for a total of up to 90 TB of storage space. If you're looking for a desktop NAS that can really deliver on features and performance, I think the Synology DiskStation DS1515+ should make your list.
