SIRIS, ALTO, and NAS: 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

s4pchart.jpgFigure 1: SIRIS VM bootup time (click to enlarge)

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

Was this article helpful?

2 out of 2 found this helpful

You must sign in before voting on this article.

Want to talk about it? Have a feature request?

Head on over to our Datto Community Forum or the Datto Community Online.

For more Business Management resources, see the Datto RMM Online Help and the Autotask PSA Online Help .

Still have questions? Get live help.

Datto Homepage