Reviewing the Synology DS1817+ with M2D17

Benchmark - Virtual Machine's Performance with SSD Cache

The Ubuntu 16.04 LTS virtual machine on the DS1817+.

One of the queries we get is whether will the virtual machines (under Synology Virtual Machine Manager) benefit from the SSD cache on the Synology NAS?

To find out whether Synology Virtual Machine Manager will benefit from SSD cache, we will be using Fio to benchmark the virtual machine’s performance on DS1817+. Fio will be running within the virtual machine under the following scenarios:

  • DS1817+’s SSD cache is not enabled;
  • DS1817+’s SSD read cache is enabled; and
  • DS1817+’s SSD read-write cache is enable.

We will be using a Ubuntu 16.04 LTS Linux OS as the virtual machine for this benchmark. Why not a Microsoft Windows OS? Well, it is to standardise the testing tool – Fio.

The virtual machine have the following configuration:

  • Ubuntu 16.04 LTS
  • 2 vCPU
  • 8GB RAM
  • 50GB vHDD (Virtual disk controller: virtio)

The SSD cache works by moving frequently accessed data onto the faster storage (i.e. SSD) so that the system need not wait for the slower storage to respond.

Hence, we will go through a phrase of preconditioning before the actual benchmark test:

  • Preconditioning. 5 sets of writing and reading from the pre-prepared files to allow data to be cache onto the SSD cache;
  • Benchmark. 1 set of writing and reading from the same pre-prepared files.

For each sets, the IO will be 70% reads and 30% writes in 8KB blocksize for 60 seconds. The order of reads and writes are randomized.


Virtual Machine’s Performance SSD Cache Benchmark Summary

The benchmark results from the virtual machine under various SSD cache configurations are as follow.

Read (MB/s)Write (MB/s)
Without SSD Cache 2.56 1.13
SSD Read Cache – WD Blue 250GB M.2 3.73 1.62
SSD Read Cache – Samsung 850 EVO 250GB M.2 3.75 1.63
SSD Read-write Cache 10.88 4.67

Avg Read Latency (ms) Max Read Latency (ms) Avg Write Latency (ms) Max Write Latency (ms)
Without SSD Cache 342.72 2,999.3 329.68 2,998.3
SSD Read Cache – WD Blue 250GB M.2 237.32 3,707.3 224.54 3,356.9
SSD Read Cache – Samsung 850 EVO 250GB M.2 233.89 3,619.3 227.29 3,618.8
SSD Read-write Cache 81.56 831.56 77.46 831.14

Without SSD Cache 327 144
SSD Read Cache – WD Blue 250GB M.2 477 207
SSD Read Cache – Samsung 850 EVO 250GB M.2 480 208
SSD Read-write Cache 1392 597

Findings when SSD read cache is enabled

When SSD read cache is enabled, both the virtual machine’s read and write latencies by the noticeably dropped. Both read and write IOPS improved with reads having the most improvement. Both read and write throughput improved.

Findings when SSD read-write cache is enabled

When SSD read-write cache is enabled, we observed great reduction in terms of read and write latencies. There is approximately 280% to 400% reduction in reading and writing latencies.

Similarly, stark improvement in both throughput and IOPS were also observed. Input/ Output per second (IOPS) also improved as much as 400%.

4 thoughts on “Reviewing the Synology DS1817+ with M2D17

  • July 28, 2017 at 11:16 am

    drool ~~~~

  • August 31, 2017 at 4:23 am

    i’ve been looking at upgraded NAS offerings. this seems like a great choice, my workflows are mostly IOPS limited, so this would represent a significant increase in performance and a significant decrease in keyboard smashing stress.

  • January 10, 2018 at 10:50 am

    Good review. Do you know if it possible to use an M.2 SSD installed in the M2D17 card as an extra storage device? Such as using it to run all your app’s etc (docker, virtual machines…) instead of running them off the array. I currently use slot 8 with an SSD installed for this purpose

  • January 10, 2018 at 12:32 pm

    Hi Darren,

    Unfortunately, we can’t use the SSD on the M2D17 as storage volume. It will just appear as SSD cache.

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