StorMagic SvSAN 6.3 review: Flawless highly available storage at the edge

Data generation at the network edge is increasing so rapidly that businesses with distributed IT operations are finding it makes more sense to process it at their remote sites rather than push it the way back to the data center. Storing data at the edge demands good security practices and if it's business-critical, then high availability is another essential requirement.

Software-defined storage (SDS) is the answer but many solutions don't lend themselves well to edge deployments as they can be expensive to implement and complex to manage. StorMagic's SvSAN stands out as this highly cost-effective SDS solution is designed to be easy to deploy and simple to manage.

Supporting VMware, Hyper-V, and Linux KVM hosts, SvSAN is deployed as virtual storage appliances (VSAs) to create a highly available storage cluster using only two servers where it implements synchronous mirroring between them. StorMagic avoids vendor lock-in as SvSAN can use any industry standard x86 servers and each VSA only requires a minimum of one virtual CPU (vCPU) and 1GB of memory.

Many SDS products need three servers to maintain data integrity after a mirror failure but SvSAN isn't one of them. Its witness acts as a quorum service that can be shared between up to 1,000 clusters and is small enough to be run on a Raspberry Pi or even a NAS appliance that provides a virtual machine manager application – StorMagic also offers a WaaS (Witness as a Service) option for cloud deployments.

StorMagic SvSAN 6.3: Swift installation

To create a dual server SvSAN cluster, we used Dell PowerEdge and HPE ProLiant Xeon Scalable rack servers. We installed VMware ESXi 8 on each one and used the Dell server to host VMware vCenter Server.

There are some prerequisites as you need to select the network ports you want to use and ensure all iSCSI traffic is placed on a dedicated virtual switch with VMware's iSCSI service enabled. StorMagic's plug-in VM makes light work of VSA creation as it adds a new configuration option at the vSphere Client datacenter level.

It provides a wizard for pushing VSAs to single or multiple ESXi hosts and choosing a datastore that will be allocated to the VSAs as shared storage. Optional features enabled with add-ons are predictive memory and SSD caching plus data encryption using a KMS (key management server).

The plug-in can also deploy a witness VM but this must obviously not be on the same physical machines as the SvSAN cluster nodes. We opted to install it on a low-cost Synology DS1621+ desktop NAS by uploading the witness VMDK file to the appliance and using DSM's Virtual Machine Manager import function to create a new VM. On completion, all we had to do was check on each VSA's web console that they had automatically discovered the witness and apply it to them.

StorMagic SvSAN 6.3: Management

StorMagic offers a big choice of management tools with the VMware SvSAN plug-in providing quick access to the VSAs and shared data stores with options to grow, migrate, mount, extend, or destroy storage pools. Each VSA also has its own web interface which provides full access to all SvSAN features.

Along with views of overall VSA status and events, you can run firmware upgrades, monitor performance statistics graphs, and configure your targets, initiators, and pools. Once initiators have been logged in, they appear in the web interface and can be assigned to selected targets.

We created a 512GB shared storage pool using the plug-in and swapped it over to the VSA interface to monitor its progress. The initial synchronization took 54 minutes and on completion, a new iSCSI target was automatically created for it.

StorMagic's Edge Control cloud-hosted service will appeal to businesses with multiple remote deployments as it provides centralized management and monitoring of all their SvSAN clusters from a single portal. We deployed the Edge Control Orchestrator VM to one of our ESXi 8 hosts and after setting up secure login credentials and 2FA for our cloud account, we could view our entire SvSAN estate from its dashboard and run tasks such as applying for new licenses, remotely upgrading VSA firmware or rebooting them.

StorMagic SvSAN 6.3 review: High availability testing

To test failover capabilities, we called up a separate Windows Server 2022 host with a dual Gigabit MPIO iSCSI connection to one of our cluster targets. Using Iometer, we recorded raw sequential read rates of 226MB/sec with both nodes available – the maximum we would expect to see for this connection.

While the test was running, we created a VSA failure using every scenario we could think of which included shutting down one VSA host server, powering a VSA down, and removing the network cable for the iSCSI backend service on one of the VSA hosts. As we tried each test, we received timely alerts and saw Iometer continue unabated, albeit at half speed.

When powering the VSA back up, we kept an eye on its progress from the active VSA's web console and saw it boot up and automatically resynchronize the mirror in only 61 seconds. Once the VSA was back online we watched Iometer return to full speed.

In one scenario, we isolated a VSA from both the cluster and witness and watched the witness take the VSA and mirror plexes offline to avoid the dreaded split-brain condition where both nodes can't communicate with each other but continue to present shared storage resources. When the VSA was returned to active duty, we saw the same fast resynchronization process with our test Windows server never losing contact with its iSCSI target.

StorMagic SvSAN 6.3 review: Is it worth it?

StorMagic's simplified licensing schemes for SvSAN are based purely on the amount of storage plus the number of cluster nodes required and are available as perpetual or subscription licences. It looks very good value with a base yearly subscription licence for 2TB and one node costing around £1,200.

We found SvSAN easy to install and once we had the hypervisor host systems prepped, we were able to deploy it in around an hour. Add in our perfect failover score and you have an ideal solution for SMBs and larger businesses with multiple edge deployments that need cost-effective, highly available storage for business-critical applications.