SIRIS, ALTO, and NAS: SIRIS 3 vs SIRIS 4 Enterprise Comparison



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


  • Datto SIRIS 3 Enterprise
  • Datto SIRIS 4 Enterprise


Hardware comparison

   SIRIS 3 Enterprise  SIRIS 4 Enterprise  Improvements in SIRIS 4
 CPU  Intel Broadwell  Intel Cascade Lake

 Greater CPU core count

 40% higher CPU performance


 4x channel

 Up to 32 GB per  DIMM

 Up to 512 GB DIMM

 6x channel

 Up to 64 GB per DIMM

 Up to 1 TB DIMM

 More channels

 More memory bandwidth

 More capacity

 ZFS SLOG  None  Intel Optane NVMe

 10x faster VM boot 

 Improved VM IOPS

 NIC  2x 10 Gbe  2x 10 Gbe + 2x 1 Gbe  2x additional 1 Gbe NIC
 Hard Drive  Up to 6 TB HDD  Up to 12 TB HDD

 Larger capacity drive

 Saves rack space

 Backplane  Active backplane  Passive backplane  Improved reliability
 Chassis  2U and 4U  2U only

 Denser system

 Saves rack space

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 Enterprise (S3E): S3E36, dual Intel 2650 v4, 9x 6TB HDD, 128GB memory
  • SIRIS 4 Enterprise (S4E): S4E36, dual Intel 4216, 9x 6TB HDD, 128GB memory
  • Virtual machines for the agents were spun up one by one, and boot time was measured.

Test results

  • S4E bootup time is much faster: 4 VMs take 5 minutes, ~9x faster than S3E (44 minutes). 
  • S3E takes longer to boot, especially when more VMs are running.
  • S4E curve is linear and maintains consistent bootup time, which means that it can handle more VMs at the same time.
VM boot up time in minutes (cumulative)
Number of VMs SIRIS 3 Enterprise SIRIS 4 Enterprise
 1  3  0.7
 2  13  2
 3  28  3
 4  44  5
 5  62  6
 6  80  8
 7  98  10
 8  116  12

s4bootup.jpgFigure 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 Enterprise (S3E): S3E36, dual Intel 2650 v4, 9x 6TB HDD, 128GB memory installed.
  • Siris 4 Enterprise (S4E): S4E36, dual Intel 4216, 9x 6TB HDD, 128GB memory installed.
  • Test tool: diskspd. Storage performance tool written by Microsoft. Refer to (external link)  for details.
  • Engineers ran diskspd in a Windows VM and measured the performance.

Test results

  • Test 1-2 (100% write test): S4E gains 2000%-7000% improvement over S3E because SLOG offloads synchronous write away from the pool, and frees up resources for real application.
  • Test 3-4 (100% read test): S4E shows 20-30% improvement over S3E. This result is reasonable as slog is a write buffer, doesn’t help reading speed directly.
  • Test 5 (70% read and 30% write): S4E is 71x times faster. Slog improves overall system performance when the system has a mixed workload.
IOPS (diskspd) Test results
   Test  S3E IOPS  S4E IOPS  Percent   improvement
 1 Random write
(storage/incremental backup)
  206  14850  7097%
 2 Sequential write
(storage/backup/video surveillance)
 660  17525  2554%
 3 Random read
(Desktop/web server)
 22361  29597  32%
 4 Sequential read
(Video streaming/application server)
 26337  31803  21%
 5 Random 70% read, 30% write
(Database query/file server/email)
 243  17505  7104%


  • S4E is 9x faster at VM boot up because ZFS SLOG offloads a high-latency synchronous write from the pool drive and reduces data IO latency, thereby reducing the time to boot a VM.
  • S4E has 25-70x better IOPS within the VM for write-related workload, thereby improving VM performance for a variety of real-time workloads.

Additional Resources

Was this article helpful?

1 out of 1 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