Why Multi-Tier Storage Support Matters More Than Ever

With the rise of QLC, TLC, and MLC SSDs, alongside traditional HDDs, multi-tier storage support has become more critical than ever. Not all workloads demand the highest-performing storage, and organizations require the ability to balance performance, endurance, and efficiency. A vSAN solution must facilitate the seamless movement of workloads across storage tiers without downtime, ensuring optimal resource utilization.

The Evolution of Storage Tiers

In the past, storage tiers were flash vs. HDD. Now, flash storage itself has multiple performance levels:

• QLC SSDs – High-capacity, cost-efficient, but with lower write endurance.
• TLC SSDs – A balance of performance and endurance, making them ideal for most workloads.
• MLC SSDs – High-performance, enterprise-grade, with superior endurance for write-intensive applications.
• HDDs – Still useful for archival storage and workloads that don’t require fast access.

While several solutions support a couple of tiers, the growing range of SSD types means that four to five tiers should now be the standard. A vSAN alternative must allow each workload to reside on the appropriate storage tier and provide the flexibility to move VMs between these tiers as needed.

Why Multi-Tier Storage Support is Essential

A modern vSAN alternative must allow IT teams to:

• Optimize Performance and Longevity – Storage wear varies depending on the NAND type. Frequently written data should reside on MLC or TLC SSDs, while read-heavy or archival data can move to QLC SSDs or HDDs.
• Reduce Unnecessary Expenditures – Not all workloads require premium high-performance storage. Assigning less critical workloads to lower-cost tiers extends storage budgets.
• Maximize Storage Efficiency – Keeping hot data on high-performance SSDs while offloading colder data prevents expensive storage tiers from being over-utilized.
• Ensure Long-Term Scalability – As storage technology evolves, supporting multiple SSD types ensures long-term adaptability instead of being locked into a limited number of tiers.

Live Migration: The Key to Tiering Without Downtime

A vSAN solution must support live VM storage migration, allowing workloads to move between storage tiers without disruption.

• Move workloads seamlessly as demands change—scale up during peak usage and shift back to cost-effective storage when demand drops.
• Upgrade storage without downtime, migrating VMs to new hardware while still running.
• Implement a true disaster recovery strategy by keeping active workloads on high-speed storage while storing replicated data on a secondary tier.

Why Automatic Tiering Isn’t Always the Best Answer

Some storage solutions implement automated tiering, relocating data across storage levels according to access patterns. While this concept is attractive in theory, it frequently leads to unpredictable performance, increased metadata complexity, and possible conflicts among storage classes. Manual control and live migration allow IT teams to achieve accurate workload placement without unforeseen reallocations.

Data Locality is No Longer Necessary

Data locality is another form of tiering that was popular in the era of a single small flash tier and HDDs. Solutions built around this concept spend significant computing resources attempting to ensure that all the data for a VM resides on the same node as the VM itself.

However, this approach is now outdated and creates more problems than it solves:

• Unnecessary resource consumption – Constantly shifting data between nodes wastes CPU and network bandwidth.
• Complex failover scenarios – When a node fails, the system must reconfigure data placement, increasing recovery time.
• Inflexible VM migration – VMs should be able to move freely between nodes without the burden of waiting for data to “catch up.”

Modern vSAN solutions should distribute data evenly across storage nodes and use an efficient storage protocol that can fully utilize 10GbE or higher internode connectivity. By taking advantage of high-speed networking and smart data distribution, vSAN solutions can enhance efficiency while removing outdated data locality constraints.

How VergeOS Delivers True Multi-Tier Storage

VergeOS fully supports multiple SSD and HDD tiers with live migration, ensuring workloads run on the right storage at the right time.

• Seamless live VM storage migration between QLC, TLC, MLC SSDs, and HDDs.
• Full flexibility to mix and match storage types within the same environment.
• Policy-driven workload placement for optimal performance, endurance, and efficiency.
• Support for four to five storage tiers to align with evolving SSD technology.

Modern storage demands require modern flexibility. With VergeOS, IT teams can create efficient, high-performance storage strategies that evolve with technology, instead of being locked into a single-tier solution.

For more insights on how storage architecture impacts recovery and performance, check out our related blog:

🔗 Understanding vSAN Snapshots

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