Virtual storage area network technology represents a fundamental shift in software defined storage by abstracting local physical disks into a logical pool of shared resources. Within the modern technical stack, vsan architecture specs define how hyper converged infrastructure (HCI) manages data persistence across distributed clusters. This architecture eliminates the traditional reliance on external Fibre Channel or iSCSI arrays. By integrating storage directly into the hypervisor, vSAN moves the data plane closer to the compute layer; this reduces latency and simplifies the hardware lifecycle. In network and cloud infrastructure environments, the primary problem involves the rigid silos of compute and storage which create performance bottlenecks during peak concurrency. The solution provided by vSAN is a distributed object based file system that utilizes a high speed private network to synchronize data across nodes. This technical manual outlines the rigorous standards required to engineer, deploy; and maintain a high performance vSAN environment.
TECHNICAL SPECIFICATIONS
| Requirement | Default Port/Operating Range | Protocol/Standard | Impact Level (1-10) | Recommended Resources |
| :— | :— | :— | :— | :— |
| Network Interface | 10GbE / 25GbE / 100GbE | IEEE 802.3ae/by/bj | 10 | Dual 25GbE SFP28 NICs |
| Multicast/Unicast | Port 2233 (UDP) | IGMPv3 / Unicast | 8 | L3 Managed Switch |
| Cache Tier Device | < 10ms Latency | NVMe / SAS4 | 9 | High Endurance SSD (3+ DWPD) |
| Capacity Tier Device | < 50ms Latency | SATA / SAS / NVMe | 7 | Read Intensive SSD or HDD |
| Boot Medium | 32GB – 128GB | M.2 / SATADOM | 4 | Industrial Grade Flash |
| Cluster Memory | 32GB min / 1TB+ max | DDR4/DDR5 ECC | 6 | 128GB+ RAM per Node |
| Thermal Management | 20C – 25C Ambient | ASHRAE Class A1-A4 | 5 | Active Airflow Control |
THE CONFIGURATION PROTOCOL
Environment Prerequisites:
Before initiating vSAN deployment, architects must verify that all hardware resides on the VMware Compatibility Guide. Version alignment is critical; ESXi hosts must run version 7.0 Update 3 or 8.0 to support the latest vSAN Express Storage Architecture (ESA). Network switches must support Jumbo Frames with an MTU of 9000 to minimize overhead during large block transfers. User permissions must include Global Configuration rights within vCenter Server. Furthermore, ensure that the physical link layer displays zero packet-loss and minimal signal-attenuation across fiber runs, as vSAN is highly sensitive to network instability.
Section A: Implementation Logic:
The theoretical foundation of vsan architecture specs relies on encapsulation of virtual machine data into discrete objects. Unlike traditional LUN-based storage, vSAN is policy driven. When a VMDK is created, the system breaks it into components based on the assigned Storage Policy Based Management (SPBM) rules. This logic ensures that data placement is idempotent: the resulting state always matches the policy regardless of the initial disk condition. By distributing these components across different failure domains, the system achieves high availability without requiring redundant physical controllers. The use of a distributed metadata directory ensures that every host in the cluster knows the location of any specific object component.
Step-By-Step Execution
1. VMkernel Interface Initialization
The primary communication channel for storage traffic must be isolated. Using the terminal, execute esxcli network ip interface add -i vmk1 -p “vSAN-PortGroup” to create the dedicated interface. Following creation, tagging is mandatory: esxcli network ip interface tag add -i vmk1 -t VSAN.
System Note: This command initializes the vSAN-specific stack within the VMkernel. It assigns a unique MAC address and IP to the storage traffic, ensuring that the payload of storage I/O is physically separate from management or vMotion traffic.
2. Physical Disk Claiming and Grouping
Identify the available NVMe or SSD devices using esxcli vsan storage list. For legacy Original Storage Architecture (OSA), a disk group must be formed using one cache device and one or more capacity devices. Execute esxcli vsan storage add -s
System Note: The kernel maps the local SCSI or NVMe identifiers to the vSAN distributed object manager. The cache device is formatted to handle write buffering and read caching, significantly reducing the effective latency for guest operating systems.
3. Cluster Metadata Synchronization
Once the disks are claimed, join the host to the vSAN cluster object. This is typically handled through the vCenter API, but can be verified via esxcli vsan cluster join. Ensure the sub-cluster UUID is consistent across all nodes.
System Note: This step synchronizes the cluster membership list. The cluster master node begins heartbeat monitoring of all subordinates; any divergence in the cluster membership will trigger an immediate re-evaluation of object health.
4. Storage Policy Application
Define the Number of Failures to Tolerate (FTT). For RAID-1 (Mirroring), the policy requires at least three hosts. For RAID-5/6 (Erasure Coding), a minimum of four to six hosts is required. Apply the policy using the spbm command line tool or vSphere Client.
System Note: The vSAN CLOM (Cluster Level Object Manager) calculates the placement map. It ensures that parity bits or mirrored copies are placed on separate physical chassis to mitigate the risk of a total node failure.
Section B: Dependency Fault-Lines:
Installation failures frequently stem from firmware-driver mismatches on the storage controller. If the driver is not certified for the specific vsan architecture specs in use, the system may experience intermittent command timeouts. Another common bottleneck is the thermal-inertia of high density NVMe drives; if the drive temperatures exceed 70C during heavy resynchronization, internal throttling will occur, causing a massive drop in throughput. Ensure the server chassis provides sufficient CFM (cubic feet per minute) of airflow to maintain optimal operating temperatures.
THE TROUBLESHOOTING MATRIX
Section C: Logs & Debugging:
When a vSAN component enters an “Absent” or “Degraded” state, the first point of inspection is /var/log/vsansystem.log. This log capture details the transitions of the object manager and helps identify if the issue is a physical disk failure or a network partition.
For real time monitoring of I/O performance, utilize the vSAN Observer tool or the native esxtop utility. Press v within esxtop to view virtual machine storage stats. Look for high values in the “DAVG” (Device Average Latency) and “KAVG” (Kernel Average Latency) columns. If “KAVG” is high, the bottleneck is within the ESXi storage stack; if “DAVG” is high, the physical hardware is struggling to keep up with the concurrency of the workload.
In cases of network partitioning, check for “Master” vs “Agent” roles using esxcli vsan cluster get. If multiple masters exist, a “split-brain” scenario has occurred due to a network break. Verify the physical switch logs for STP (Spanning Tree Protocol) transitions or port flapping which could be causing high packet-loss.
OPTIMIZATION & HARDENING
– Performance Tuning: To increase throughput, enable Jumbo Frames across the entire path. This reduces the number of frames the CPU must process, lowering the interrupt overhead. For workloads with high write concurrency, consider increasing the stripe width in the VM storage policy. This spreads the data across more physical spindles/flash modules.
– Security Hardening: Implement vSAN encryption at the cluster level. This uses a Key Management Server (KMS) to encrypt data at rest. Ensure the firewall rules on the ESXi hosts are restricted to only allow vSAN traffic on the dedicated VLAN. Use esxcli network firewall ruleset set -e true -r vsan.
– Scaling Logic: vSAN scales linearly. Adding a node adds both compute and storage capacity. When scaling, ensure the “Slack Space” remains at least 25 percent of the total capacity. This space is required for internal maintenance tasks like rebalancing and policy compliance checks during a node failure.
THE ADMIN DESK
1. How do I fix a “Disk Formatted Version” error?
This usually occurs after a vSphere upgrade. Navigate to the vSAN Cluster settings and trigger a “Disk Format Upgrade.” This process is idempotent and will migrate data to the new format node by node without downtime.
2. Why is my resynchronization speed so slow?
Check the Adaptive Resync settings. vSAN prioritizes guest I/O over background synchronization. If the cluster is under high load; resync will be throttled. You can manually adjust the resync bandwidth limit in the cluster advanced options.
3. What causes “Ineligible” disks during setup?
Disks must be completely blank with no partition tables to be claimed. Use partedUtil delete to remove existing partitions on the device path, such as /vmdk/devices/disks/mpx.vmhba… before attempting to add them to a disk group.
4. How do I handle a “Network Partitioned” warning?
Verify that all hosts can ping each other over the vSAN VMkernel interface using vmkping -I vmk1
5. What is the impact of “Object Data Health” warnings?
These warnings indicate that a VM’s data redundancy is at risk. This happens during node maintenance or disk failure. If the state is “Absent,” the system is waiting for the component to return before rebuilding; default wait time is 60 minutes.
