Storage Virtualization with VMware

Overview

Storage virtualization is a critical component of any VMware environment. Understanding how to properly configure and manage storage resources ensures optimal performance, availability, and scalability for your virtual infrastructure.

VMware Storage Architecture

Storage Protocols Supported

VMware ESXi supports multiple storage protocols, each with its own advantages and use cases:

SCSI-Based Protocols

• iSCSI: IP-based storage protocol
• Fibre Channel (FC): High-performance SAN protocol
• Fibre Channel over Ethernet (FCoE): Combines FC with Ethernet

File-Based Protocols

• NFS: Network File System for shared storage
• VMFS: VMware's cluster file system for shared storage

Storage Device Types

• Local Storage: Direct-attached storage on ESXi hosts
• Shared Storage: Accessible by multiple ESXi hosts
• Remote Storage: Offsite or cloud-based storage

Datastore Types

VMFS (Virtual Machine File System)

VMFS is VMware's proprietary cluster file system designed for shared storage environments.

VMFS Features:

• Cluster file system supporting multiple hosts
• Block-level access to storage
• Supports large volumes and files
• Designed for virtualization workloads

VMFS Versions:

• VMFS-3: Legacy version, still supported
• VMFS-5: Current version with enhanced features
• VMFS-6: Latest version with 64TB file size support

Creating VMFS Datastores:

1. Access Storage Configuration

   • Navigate to Host > Storage
   • Click "New Datastore"

2. Select Datastore Type

   • Choose "VMFS"
   • Select available storage device

3. Configure Datastore

   • Assign datastore name
   • Select VMFS version
   • Set block size

NFS (Network File System)

NFS provides file-level access to shared storage over IP networks.

NFS Advantages:

• Simpler management than block storage
• Lower cost compared to SAN
• Good for backup and archive

NFS Configuration:

1. Prepare NFS Server

   • Configure NFS export on NAS device
   • Set appropriate permissions

2. Mount NFS Datastore

   • Navigate to Host > Storage
   • Click "New Datastore"
   • Select NFS type
   • Enter server IP and path

NFS Versions:

• NFSv3: Traditional version, widely supported
• NFSv4.1: Enhanced security and performance

vSAN (Virtual SAN)

vSAN is VMware's software-defined storage solution that creates shared storage from local storage devices.

vSAN Architecture:

• Witness Components: Maintains quorum
• Object Components: Store virtual machine data
• Host Components: Manage storage on each host

vSAN Features:

• Hyper-converged infrastructure
• Policy-based management
• Built-in deduplication and compression
• Encryption capabilities

Storage Configuration and Management

Storage Discovery and Setup

iSCSI Configuration

1. Enable iSCSI Adapter

   • Go to Storage Adapters
   • Enable software iSCSI adapter

2. Configure Network

   • Assign VMkernel port for iSCSI traffic
   • Configure network isolation if needed

3. Discover Targets

   • Dynamic discovery: Automatically find targets
   • Static discovery: Manually add target addresses

4. Authentication

   • CHAP authentication for security
   • Mutual CHAP for bidirectional authentication

Fibre Channel Configuration

1. Install HBAs: Install Fibre Channel host bus adapters
2. Zone Configuration: Configure zoning on SAN fabric
3. LUN Mapping: Map LUNs to ESXi hosts
4. Multipathing: Configure path redundancy

Multipathing Configuration

Path Selection Policies (PSP)

• VMW_PSP_FIXED: Use specific preferred path
• VMW_PSP_RR: Round-robin load balancing
• VMW_PSP_MRU: Most recently used path

Storage Array Type Plugins (SATP)

• Determine default PSP for storage arrays
• Handle array-specific features
• Manage path failover

Storage Performance Optimization

Cache Configuration

• Host-side caching: Use local SSD for read/write cache
• Array-side caching: Leverage storage array cache
• Storage I/O Control: Manage storage resources

Storage I/O Control (SIOC)

• Automatic Thresholds: Dynamic performance monitoring
• Manual Thresholds: Set custom performance targets
• Reservation-Based Admission Control: Ensure resource reservations

Virtual Machine Storage Management

Virtual Disk Types

Thick Provisioned Lazy Zeroed

• Full space allocated at creation
• Blocks zeroed on demand
• Faster creation time

Thick Provisioned Eager Zeroed

• Full space allocated at creation
• All blocks zeroed immediately
• Required for Fault Tolerance

Thin Provisioned

• Space allocated as needed
• Storage overcommitment possible
• Space reclamation support

Storage vMotion

• Live migration: Move VM storage without downtime
• Cross-vCenter: Migrate between different vCenters
• Storage policy compliance: Ensure policy adherence

Storage Policies

• Virtual SAN Policies: Define vSAN requirements
• Storage Profile: Abstract storage capabilities
• Policy-Based Management: Automated storage placement

vSAN Configuration and Management

vSAN Requirements

• Minimum 3 hosts (2-node with witness)
• Specific hardware compatibility
• Network configuration for vSAN traffic
• Sufficient local storage capacity

vSAN Setup Process

1. Enable vSAN: Activate vSAN on cluster
2. Configure Network: Dedicated vSAN network
3. Claim Storage: Add capacity devices to vSAN
4. Set Policies: Define storage policies for VMs

vSAN Policies

• Number of Failures to Tolerate: Defines fault tolerance
• Flash Read Cache: Cache tier configuration
• Object Space Reservation: Thin provisioned reservations
• Disk Striping: Performance optimization

Storage Monitoring and Troubleshooting

Performance Metrics

• Latency: Time for I/O operations to complete
• Throughput: Amount of data transferred per unit time
• IOPS: Input/output operations per second
• Queue Depth: Number of pending I/O operations

Monitoring Tools

• vSphere Client: Built-in performance charts
• esxtop: Real-time storage performance
• vRealize Operations: Advanced analytics
• Storage vendor tools: Array-specific monitoring

Common Storage Issues

• Performance Degradation: Bottlenecks and latency issues
• Connectivity Problems: Path failures and timeouts
• Capacity Issues: Running out of storage space
• Multipathing Issues: Path selection and failover problems

Troubleshooting Steps

1. Identify Symptoms: Document performance issues
2. Check Storage Paths: Verify connectivity
3. Analyze Performance: Review metrics and trends
4. Examine Logs: Check system and storage logs
5. Validate Configuration: Confirm settings and policies

Storage Best Practices

Design Guidelines

• Network Segregation: Dedicated storage networks
• Redundancy: Multiple paths to storage
• Capacity Planning: Monitor and forecast usage
• Performance Requirements: Match storage to workload needs

Performance Optimization

• Alignment: Proper partition alignment
• Block Size: Optimize for workload type
• Caching: Use appropriate caching strategies
• Protocol Selection: Choose right protocol for use case

Security Considerations

• Authentication: Secure storage access
• Encryption: Encrypt data at rest and in transit
• Network Security: Isolate storage traffic
• Access Controls: Limit administrative access

Storage Migration Strategies

From Local to Shared Storage

• VMware Converter: Physical-to-virtual conversion
• Storage vMotion: Live migration of VMs
• Backup and Restore: Traditional migration approach

From Traditional to vSAN

• Assessment: Evaluate current storage needs
• Planning: Design vSAN cluster
• Migration: Move VMs with Storage vMotion
• Optimization: Fine-tune vSAN configuration

Conclusion

Storage virtualization in VMware provides flexible, scalable, and high-performance storage solutions for virtual environments. Proper planning and configuration of storage resources is essential for a successful virtualization deployment.

In the next article, we'll explore high availability and fault tolerance features in VMware, covering how to ensure business continuity and minimize downtime.