If you are running VMware on top of DataCore SANsymphony, you might be manually adding ESXi hosts by their IQNs or WWNs. While that works, you’re missing out on the „secret sauce“ of a software-defined data center.
By registering your vCenter Server directly into the DataCore Management Console, you bridge the gap between your compute and storage layers.
Why register vCenter in SANsymphony?
Registering vCenter isn’t just about „seeing“ your VMs; it’s about deep orchestration. When SANsymphony and vCenter shake hands, several manual tasks simply disappear:
- Automated Inventory Management: SANsymphony automatically discovers every ESXi host, folder, and cluster. If you add a new node to your VMware cluster, DataCore sees it instantly.
- Storage-Aware Provisioning: You can create and serve a Virtual Disk and have SANsymphony handle the „rescan,“ „initialize,“ and „format as VMFS“ steps automatically.
- VM-Level Granularity: You gain visibility into which specific Virtual Machines are generating the most I/O, allowing for better troubleshooting.
- vCenter Plugin Prerequisite
What Can You See? Visible ESXi Parameters in SANsymphony
Once the registration is complete, the Host Details page in SANsymphony becomes a powerful window into your VMware environment. You can monitor and verify the following parameters without ever leaving the DataCore console:
The „Must-Have“ ESXi Settings for DataCore
Even with vCenter registered, VMware needs a little fine-tuning at the hypervisor level. If you want to avoid latency spikes, ensure these advanced settings are configured in vSphere:
- Disk.DiskMaxIOSize: Set to 512 KB to prevent large I/O blocks from clogging the queue.
- Round Robin (PSP): Ensure your Path Selection Policy is set to Round Robin for all DataCore LUNs.
- IOPS=10: Change the default switching limit from 1000 to 10 to balance traffic more aggressively across paths.
- DelayedAck: Disable this for iSCSI environments to prevent artificial latency.
Automation: The PowerCLI Shortcut
Manually configuring every host is prone to error. To ensure every ESXi node in your cluster handles DataCore storage identically, use the following PowerCLI script. This script injects the exact best-practice SATP rule, ensuring that any disk identified as a „DataCore Virtual Disk“ is automatically claimed with the correct pathing and retry logic.
PowerShell
# Connect to your vCenter
Connect-VIServer -Server YOUR_VCENTER_NAME
# Target a specific cluster
$clusterName = „Your_Cluster_Name“
$hosts = Get-Cluster $clusterName | Get-VMHost
foreach ($esx in $hosts) {
Write-Host „Configuring $($esx.Name)“ -ForegroundColor Cyan
$esxcli = Get-EsxCli -VMHost $esx -V2
# Prepare the arguments to match the esxcli command exactly
$arguments = $esxcli.storage.nmp.satp.rule.add.CreateArgs()
$arguments.vendor = „DataCore“
$arguments.model = „Virtual Disk“
$arguments.satp = „VMW_SATP_ALUA“
$arguments.psp = „VMW_PSP_RR“
$arguments.pspoption = „iops=10“
$arguments.option = „disable_action_OnRetryErrors“ # Prevents path thrashing
$arguments.claimoption = „tpgs_on“ # Explicitly enables ALUA
$arguments.description = „DataCore SANsymphony ALUA Best Practice“
# Apply the Rule try {
$esxcli.storage.nmp.satp.rule.add.Invoke($arguments)
Write-Host „Successfully applied SATP rule to $($esx.Name)“ -ForegroundColor Green
} catch {
Write-Host „Rule might already exist on $($esx.Name): $($_.Exception.Message). Please delete the existing rule prior to applying new settings.“ -ForegroundColor Red
}
}
# Note: Changes take effect for new LUNs immediately.
# For existing LUNs, a host reboot or manual unclaim/claim is required.
Why these specific flags matter:
- disable_action_OnRetryErrors: This tells ESXi not to immediately mark a path as „Dead“ if it receives a retryable error, which is common during DataCore storage service restarts or transparent failovers.
- tpgs_on: This stands for Target Port Group Support. It is the „engine“ behind ALUA, allowing the ESXi host to distinguish between an Active/Optimized path (local node) and an Active/Unoptimized path (partner node).
- iops=10: By lowering the switchover threshold from 1000 to 10, you ensure the host utilizes all available Front-End ports on your DataCore nodes simultaneously, maximizing throughput.
Summary
Registering vCenter in DataCore SANsymphony turns your storage into an intelligent partner. It gives you a „single pane of glass“ to monitor ALUA status, Preferred Servers, and Port connectivity, while automating the tedious parts of host management.
Autor:
Alwin Kohl – Cyber-Resilience Evangelist, Senior Solutions Architect and Technical Pre-Sales at DataCore Software
