Monitoring vSAN in the VMware Host Client

You can use the VMware Host Client to monitor the vSAN environment of your ESXi host.

vSAN Concepts

VMware vSAN uses a software-defined approach that creates shared storage for virtual machines.

It virtualizes the local physical storage resources of ESXi hosts and turns them into pools of storage that can be divided and assigned to virtual machines and applications according to their quality-of-service requirements. vSAN is implemented directly in the ESXi hypervisor.

You can configure vSAN to work as either a hybrid or all-flash cluster. In hybrid clusters, flash devices are used for the cache layer and magnetic disks are used for the storage capacity layer. In all-flash clusters, flash devices are used for both cache and capacity.

You can activate vSAN on existing host clusters, or when you create a new cluster. vSAN aggregates all local capacity devices into a single datastore shared by all hosts in the vSAN cluster. You can expand the datastore by adding capacity devices or hosts with capacity devices to the cluster. vSAN works best when all ESXi hosts in the cluster share similar or identical configurations across all cluster members, including similar or identical storage configurations. This consistent configuration balances virtual machine storage components across all devices and hosts in the cluster. Hosts without any local devices also can participate and run their virtual machines on the vSAN datastore.

In vSAN Original Storage Architecture (OSA), each host that contributes storage devices to the vSAN datastore must provide at least one device for flash cache and at least one device for capacity. The devices on the contributing host form one or more disk groups. Each disk group contains one flash cache device, and one or multiple capacity devices for persistent storage. Each host can be configured to use multiple disk groups.

In vSAN Express Storage Architecture (ESA), all storage devices claimed by vSAN contribute to capacity and performance. Each host's storage devices claimed by vSAN form a storage pool. The storage pool represents the amount of caching and capacity provided by the host to the vSAN datastore.

For best practices, capacity considerations, and general recommendations about designing and sizing a vSAN cluster, see the VMware vSAN Design and Sizing Guide.

Characteristics of vSAN

The following characteristics apply to vSAN, its clusters, and datastores.

vSAN includes numerous features to add resiliency and efficiency to your data computing and storage environment.

Table 1. vSAN Features

Supported Features	Description
Shared storage support	vSAN supports VMware features that require shared storage, such as HA, vMotion, and DRS. For example, if a host becomes overloaded, DRS can migrate virtual machines to other hosts in the cluster.
On-disk format	vSAN on-disk virtual file format provides highly scalable snapshot and clone management support per vSAN cluster. For information about the number of virtual machine snapshots and clones supported per vSAN cluster, see the Configuration Maximums documentation.
All-flash and hybrid configurations	vSAN can be configured for all-flash or hybrid cluster.
Fault domains	vSAN supports configuring fault domains to protect hosts from rack or chassis failures when the vSAN cluster spans across multiple racks or blade server chassis in a data center.
File service	vSAN file service enables you to create file shares in the vSAN datastore that client workstations or VMs can access.
iSCSI target service	vSAN iSCSI target service enables hosts and physical workloads that reside outside the vSAN cluster to access the vSAN datastore.
Stretched cluster and Two node cluster	vSAN supports stretched clusters that span across two geographic locations.
Support for Windows Server Failover Clusters (WSFC)	vSAN 6.7 Update 3 and later releases support SCSI-3 Persistent Reservations (SCSI3-PR) on a virtual disk level required by Windows Server Failover Cluster (WSFC) to arbitrate an access to a shared disk between nodes. Support of SCSI-3 PRs enables configuration of WSFC with a disk resource shared between VMs natively on vSAN datastores. Currently the following configurations are supported: Up to 6 application nodes per cluster. Up to 64 shared virtual disks per node. Note: Microsoft SQL Server 2012 or later running on Microsoft Windows Server 2012 or later has been qualified on vSAN.
vSAN health service	vSAN health service includes preconfigured health check tests to monitor, troubleshoot, diagnose the cause of cluster component problems, and identify any potential risk.
vSAN performance service	vSAN performance service includes statistical charts used to monitor IOPS, throughput, latency, and congestion. You can monitor performance of a vSAN cluster, host, disk group, disk, and VMs.
Integration with vSphere storage features	vSAN integrates with vSphere data management features traditionally used with VMFS and NFS storage. These features include snapshots, linked clones, and vSphere Replication.
Virtual Machine Storage Policies	vSAN works with VM storage policies to support a VM-centric approach to storage management. If you do not assign a storage policy to the virtual machine during deployment, the vSAN Default Storage Policy is automatically assigned to the VM.
Rapid provisioning	vSAN enables rapid provisioning of storage in the vCenter Server® during virtual machine creation and deployment operations.
Deduplication and compression	vSAN performs block-level deduplication and compression to save storage space. When you enable deduplication and compression on a vSAN all-flash cluster, redundant data within each disk group is reduced. Deduplication and compression is a cluster-wide setting, but the functions are applied on a disk group basis. Compression-only vSAN is applied on a per-disk basis.
Data at rest encryption	vSAN provides data at rest encryption. Data is encrypted after all other processing, such as deduplication, is performed. Data at rest encryption protects data on storage devices, in case a device is removed from the cluster.
Data in transit encryption	vSAN can encrypt data in transit across hosts in the cluster. When you enable data-in-transit encryption, vSAN encrypts all data and metadata traffic between hosts.
SDK support	The VMware vSAN SDK is an extension of the VMware vSphere Management SDK. It includes documentation, libraries and code examples that help developers automate installation, configuration, monitoring, and troubleshooting of vSAN.

Monitor vSAN in the VMware Host Client

You can use the VMware Host Client to monitor the vSAN environment of your ESXi host.

Prerequisites

vSAN service must be enabled in the vSphere Client before you can view the vSAN related screens for a datastore.

Procedure

1. Click Storage in the VMware Host Client inventory.
2. On the Datastores tab, click vSAN Datastore.
   The vSAN Datastore expands in the VMware Host Client navigator.
3. Click Monitor.
   You are present with the vSAN, Host, and Health tabs in the UI.

   Option	Description
   vSAN	Displays the configurations for the current host. You can edit the settings for the claiming mode and deduplication. You can also view the settings for: Encryption – vSAN supports encryption of the information for the whole vSAN datastore. ISCSI Service – Additional service through the iSCSI service. Performance Service - Collects data on how the datastore works. For example, the speed of a read/write operation.
   Hosts	Displays a list of all the hosts on the vSAN server with their IP and the fault domain they belong to.
   Health	The Health tab contains tests organized in groups. You are present with the following groups: Performance Service Network Physical disk Data Cluster Limits Each group is labeled with a status icon for an error, warning, unknown or healthy. The status of the group represents the most severe state of the test belonging to that group. To view the tests and their descriptions, click the expand icon in the top right corner of the group of interest. From the expanded card you can review all the tests belonging to the group, the result of their execution and get more information about what each test examines on the system.

4. Select the vSAN parameter that you want to monitor.

Edit Settings for a vSAN Datastore

You can edit the settings for a vSAN datastore when you must exit from a misconfigured state of the current host.

You can only edit the Claiming Mode and Deduplication settings for a vSAN datastore. These changes take effect only on the current host. They are not synced to the other hosts participating into the vSAN cluster.

Note: Only use these settings for troubleshooting.

Procedure

1. Click Storage in the VMware Host Client inventory.
2. On the Datastores tab, click a vSAN datastore from the table.
3. Click Monitor and click the vSAN tab.

   

4. Click Edit settings.
   The Edit Settings dialog box opens.
5. Change the settings.Select Auto or Manual from the Claiming Mode.

   Option	Action
   Claiming Mode	Select Auto or Manual from the Claiming Mode. If you select Auto, it automatically takes all disks and claims them in a group or groups of the same size. Note: The Auto mode is deprecated. It can only claim hybrid disk groups which are not compatible with most of the vSAN features. If you select Manual, you must manually organize the disks in groups and reclaim them by using the vSphere Web Client. For instance, selecting manual claiming mode is appropriate when the vCenter Server is unavailable.
   Deduplication	Select Enabled or Disabled for the Deduplication.

6. Click Save.