As virtualization becomes more and more popular even in home / power user settings, the importance of the iSCSI feature set of any COTS NAS can't be overstated. Starting with our ioSafe 1513+ review, we have started devoting a separate section (in the reviews of NAS units targeting SMBs and SMEs) to the evaluation of iSCSI performance. Since we have already looked at the way iSCSI LUNs are implemented in DSM in the ioSafe 1513+ review, it won't be discussed in detail.
We evaluated the performance of the DS1815+ with file-based LUNs as well as configuring a RAID-5 disk group in multiple LUNs mode and single LUN mode. The standard IOMeter benchmarks that we used for multi-client CIFS evaluation were utilized for iSCSI evaluation also. The main difference to note is that the CIFS evaluation was performed on a mounted network share, while the iSCSI evaluation was done on a 'clean physical disk' (from the viewpoint of the virtual machine).
Performance Numbers
The four IOMeter traces were run on the physical disk manifested by mapping the iSCSI target on each VM. The benchmarking started with one VM accessing the NAS. The number of VMs simultaneously playing out the trace was incremented one by one till we had all 25 VMs in the fray. Detailed listings of the IOMeter benchmark numbers (including IOPS and maximum response times) for each configuration are linked below:
Since the number of NAS units that we have put through this evaluation is limited, we have a couple of 4-bay NAS units in the comparison drop-downs above. Unfortunately, we have no graphs for apples-to-apples comparison. That said, we do see the 'single LUN on RAID' mode delivering the best performance. For some strange reason, the multiple LUNs on RAID configuration is never able to take advantage of the bonded network ports. Even the simultaneous multi-client sequential reads test always stay below 125 MBps.
File-based LUNs give maximum flexibility - thin provisioning, support for VMWare VAAI and Windows ODX. The latest versions of DSM have improved on the iSCSI feature set quite a bit. Synology's competitors have a bit of catching up to do in the iSCSI feature set area.
As more NAS units are processed, we hope this section will provide readers with a way to quickly get an idea of the competitive performance of a particular NAS unit when it comes to iSCSI support.
Is there any specs on how these perform when compare to a simple, business-class server that has 8-bays? Something like a Dell PowerEdge T320 that has the capability for 8 x 3.5" drives and includes a quad-port GB NIC can be had for basically the same price as the Synology here.
These larger-cost 8-bay NAS machines have a high price tag, so a natural competitor (in terms of price) seems to be servers from the standard server vendors. So I would love to see how it actually compares.
Poorly. Their only advantages over a computer are smaller and more power efficient. People will talk about how it saves so much time but you have to save quite a lot of time to make up the difference in cost between a synology and a much cheaper and faster computer.
My time, plus any employees or services I have on the NAS could cost me the initial price each *hour* if it goes down. So having one physical unit, with hot swap, and on the fly rebuild is worth the price in some cases.
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vLsL2VnDmWjoTByaVLxb - Tuesday, November 18, 2014 - link
Sorry, that was meant as a response for JeffFlanagan's post above. :\JustaUsernameorWE - Tuesday, November 18, 2014 - link
Anyone have any idea when/if they'll put Rangeley in a 2bay unit? Not thrilled with the current 2 bay market.ganeshts - Tuesday, November 18, 2014 - link
Synology doesn't have one (yet), but the Seagate NAS Pro 2-bay should fit your needshttp://www.seagate.com/products/network-attached-s...
It is based on Rangeley too, albeit a 2C/2T model running at 1.7 GHz.
romrunning - Tuesday, November 18, 2014 - link
Is there any specs on how these perform when compare to a simple, business-class server that has 8-bays? Something like a Dell PowerEdge T320 that has the capability for 8 x 3.5" drives and includes a quad-port GB NIC can be had for basically the same price as the Synology here.These larger-cost 8-bay NAS machines have a high price tag, so a natural competitor (in terms of price) seems to be servers from the standard server vendors. So I would love to see how it actually compares.
peterfares - Tuesday, November 18, 2014 - link
Poorly. Their only advantages over a computer are smaller and more power efficient. People will talk about how it saves so much time but you have to save quite a lot of time to make up the difference in cost between a synology and a much cheaper and faster computer.romrunning - Wednesday, November 19, 2014 - link
I also would like to know if some of the poor network performance numbers shown by these selected NAS units are also present in a full server setup.I guess we'll never know because these review units likely come with caveats on what type of "competing" devices they can reviewed against.
dgingeri - Tuesday, November 18, 2014 - link
An Atom processor, 8 bays, 2GB of memory, and 8 bays, for $1050. I could build better for less, and get more flexibility.peterfares - Tuesday, November 18, 2014 - link
BUT YOU CAN SAVE SO MUCH TIME WITH A SYNOLOGY!!!!!Haha. Those peoples time must be worth a lot. And if it's worth that much, why are they going for a Synology and not something better?
rpg1966 - Tuesday, November 18, 2014 - link
:rolleyes:DiHydro - Wednesday, November 19, 2014 - link
My time, plus any employees or services I have on the NAS could cost me the initial price each *hour* if it goes down. So having one physical unit, with hot swap, and on the fly rebuild is worth the price in some cases.