Data Center

3 Tips to Optimize VMware vSAN’s Storage Management Capabilities

These steps can help storage administrators take advantage of vSAN’s powerful features.

Greg Schulz, author of several books on storage, is founder of the StorageIO Group, an IT industry analyst consultancy whose blog can be found at storageioblog.com and at twitter.com/storageio.

Storage virtualization enables data center operators to manage their storage resources through a single platform. By delivering this capability via hyperconverged infrastructure, VMware’s vSAN software allows organizations to connect their storage devices across a vSphere cluster into a shared data pool.

Pooling and centrally managing storage resources can provide valuable benefits for data center operators who take advantage of these solutions. Those who deploy vSAN should consider these three tips for optimizing its use.

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1. Optimize Tiering for Hybrid Storage Environments

Many data centers are deploying traditional hard-disk storage drives with flash storage to create hybrid environments. VMware vSAN enables administrators to optimize how data is stored in the different tiers of a hybrid environment. For example, data for the write cache should be sent to solid-state drives that are designed with high terabytes written (TBW) and drive writes per day (DWPD) metrics. Data center operators can further optimize storage by spreading drives across multiple disk groups and adapters for better performance, faster rebuilds and fault isolation.

When deploying vSAN, admins should review data footprint reduction settings for compression, deduplication and thin provisioning along Failures to Tolerate settings. FTT settings include applicable RAID/Erasure code settings to balance performance, availability and capacity. The vSAN software provides easy-to-use management interfaces and health displays to help administrators see how best to optimize these settings.

2. Set Up a Stretched Cluster over Geographic Locations

Data center operators can improve availability by leveraging vSAN stretched clusters to span geographic locations. Stretched clusters distribute compute and storage resources from adjacent racks in a server room to resources across a campus, or even to a separate data center on the other side of town (a practice also known as metro clustering). A vSAN stretched cluster can span a distance of up to 100 kilometers (62 miles) with low-latency networks.

The vSAN stretched cluster capability can reduce the cost and complexity associated with traditional metro clustering approaches, and these clusters can protect an organization against a site failure. Data center operators can make stretched clusters a part of their overall data protection strategy, combining this capability with point-in-time copy, snapshot, backup and replication approaches. Network bandwidth of 10 gigabits per second or faster is recommended for stretched clusters, as is round-trip latency of 5 milliseconds or less.

3. Establish Policies to Proactively Rebalance Storage

By setting up policies for proactive, automated vSAN cluster rebalancing, organizations can reduce the time and costs associated with storage management. Periodic rebalancing is needed when new compute resources and storage capacity are added to a cluster.

To set up proactive rebalancing, an administrator can use the vSAN user interface or command line tools to monitor activity and cluster health status. Tools within the vSAN software enable administrators to see if disk space is balanced across hosts in a cluster and to determine if a single host failure would affect vSAN capacity or cache. By default, vSAN initiates reactive rebalancing when a storage device reaches 80 percent of its capacity. An admin can change policy settings to trigger rebalancing at a lower threshold.

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