High Availability System Requirements

Minimum Recommended Configurations

The following configurations are recommended best practices for SoftNAS SNAP HA™:

  • 16 to 64 GB RAM
  • 4 vCPU (8 vCPU if volume data compression will be used extensively)
  • SSD for read cache and write log
  • Separate replication and storage traffic to dedicated physical networks
  • Replication should occur from like storage to like storage, to avoid performance bottlenecks. Different read/write speeds can potentially result in cache data loss.
minimum requirements only supply adequate performance for proof of concept or test instances. We recommend that you look at our guidance on instance sizing.
SNAP HA relies on time settings in both the primary and secondary instances. It is important to use the same time for each. If an NTP is used, configure both with the same URL.

AWS Minimum Requirements

  • Virtual Private Cloud (VPC)
  • 3 Virtual IP addresses 
    1. one used to route NAS client traffic across availability zone. This IP address must be in a separate CIDR block.
    2. one for each instance for SoftNAS StorageCenter™ remote administration. Virtual IP setup is recommended.
  • Alternatively, use a VPC with private VPN access to SoftNAS StorageCenter™ for administration, with 1 Elastic IP address for NAS client traffic
  • 2 each SoftNAS storage controller EC2 instances
  • 2 virtual interfaces on each instance. First interface is used for SoftNAS StorageCenter™ and replication, second interface for Elastic HA IP for NAS traffic
  • For storage VLAN, choose EC2 instance types for NAS clients and SoftNAS StorageCenter™ that support MTU 9000 (required for 10 GbE maximum throughput)
  • EBS disks for each storage controller's local storage
  • For highest throughput, use HVM instances with local, ephemeral SSDs for read cache, high-IOPS EBS volume (SSD) for write log and EC2 instances with 10 GbE network interfaces
  • Use EBS volumes for primary storage in RAIDz-2 configuration for best data density and RAID-10 with high-IOPS EBS volumes for best IOPS in database and transactional applications

VMware Minimum Requirements

  • HA Controller VM is required, the recommended minimum is 500MB of RAM and 1vCPU
  • 2 each SoftNAS storage controller VMs
  • 1 each HA Controller VM with 500 MB RAM and 1 vCPU configured to use VMware FT (fault-tolerance) to ensure HA Controller is always available
  • 3 each virtual NICs - separate vNIC and VLAN allocated to: 1) SoftNAS StorageCenter™ administration (E1000), 2) SnapReplicate™ block replication (E1000), 3) storage VLAN (VMXNet3)
  • For storage VLAN, configure for MTU 9000 (required for 10 GbE maximum throughput)
  • DirectPath pass-through disk controller providing direct disk access (requires Intel VT-d and disk controller supported by CentOS). This is required for best small block 4K/8K I/O and synchronous write-log and read cache performance with VMware
  • Separate disk controllers for 1) booting VMware from RAID-1 mirrored disks and 2) storage I/O
  • 4 each 10 GbE or 1 GbE physical NICS (2 active/active for VMware host management and SoftNAS administration and replication, 2 active/active for data storage)


  • Boot VMware from 32 GB USB, and dedicate disk controller for DirectPath disk I/O
  • VMDKs for SATA and SAS storage and read cache
  • InfiniBand NIC for data storage pathway

Azure Minimum Requirements

  • Virtual Private Cloud (VPC)
  • 2 SoftNAS storage controller Azure Virtual Machines 
  • Two 1 GB virtual interfaces on each instance
  • Azure Standard/Premium block storage disks.