SIRIS 3 vs SIRIS 4 Professional Comparison


This article compares hardware and virtualization performance of SIRIS 3 and SIRIS 4 Professional devices.


  • Datto SIRIS 3 Professional
  • Datto SIRIS 4 Professional


Hardware comparison

  SIRIS 3 Professional SIRIS 4 Professional Improvements in SIRIS 4
CPU Intel Broadwell Intel Skylake

40% higher CPU performance


2x channel

4X slots

Up to 128 GB DIMM total

4x channel

8x slots

Up to 256 GB DIMM total

More channels

More slots

More capacity

ZFS SLOG None Intel Optane NVMe

2x faster VM boot

Improved VM IOPS

NIC 2x 10 Gbe 2x 10 Gbe Same
Hard Drive Up to 6 TB HDD Up to 12 TB HDD

Larger capacity drive

Acoustic & Thermal Loud Quiet

Reduced noise

Balanced Thermal

Improved Operational experience

Virtualization boot time test

This test compares how fast you can recover in the event of a disaster.

Test setup

  • 10 Agents (Windows 7 server pack, new install, all identical).
  • SIRIS 3 Professional (S3P): S3P6, 2x 6 TB HDD, 64 GB memory.
  • SIRIS 4 Professional (S4P): S4P6, 2x 6 TB HDD, 64 GB memory.
  • Virtual machines for the agents were started one by one, and boot time was measured.

Test results

  • S4P bootup time is approximately 2x faster than S3P
VM bootup time in minutes (cumulative)
Number of VMs SIRIS 3 Professional SIRIS 4 Professional
1 1 1
2 2 1
3 4 2
4 5 3
5 6 4
6 8 5
7 10 6

Figure 1: SIRIS VM bootup time

IOPS virtualization performance test

This test measures input and output per second (IOPS) within a virtual machine running on the Datto device.

Test setup

  • 1 Agent (Windows 2012 R2, new install, with diskspd installed).
  • Siris 3 Professional (S3P): S3P6, 2x 6 TB HDD, 64 GB memory installed.
  • Siris 4 Professional (S4P): S4P6, 2x 6 TB HDD, 64 GB memory installed.
  • Test tool: diskspd. Storage performance tool written by Microsoft. Refer to (external link) for details.
  • Virtual machines for each agent were started and boot time was measured.

Test results

  • Test 1-2 (write test): S4P gains a 5-14x improvement over S3E because SLOG offloads high-latency synchronous write off the pool drive, which reduces data I/O latency and thereby improves VM performance significantly.
  • Test 3-4 (read test): S4P shows 20-30% improvement over S3P. Minimal read improvement as slog is a write buffer and doesn't help reading speed directly. Slog does, however, help read performance as Test 5 results show.
  • Test 5: With a mixed workload of 30% write and 70% read, similar to a database workload, the S4P is 8x times faster.
IOPS (diskspd) Test results
Test S3P IOPS S4P IOPS Percent improvement
1 Random write
(storage/incremental backup)
816 12647 1450%
2 Sequential write
(storage/backup/video surveillance)
2283 14163 520%
3 Random read
(Desktop/web server)
19208 24485 27%
4 Sequential read
(Video streaming/application server)
19914 23636 19%
5 Random 70% read, 30% write
(Database query/file server/email)
1251 12231 878%

Additional Resources