Basic esxcli Commands For vSAN Troubleshooting

images (3)

There are some very basic commands which are really useful in troubleshoting.

Use below esxcli commands to obtain information about Virtual SAN and to troubleshoot your Virtual SAN environment.

Command

Description

esxcli vsan network list

Verify which VMkernel adapters are used for Virtual SAN communication.

esxcli vsan storage list

List storage disks that were claimed by Virtual SAN.

esxcli vsan cluster get

Get Virtual SAN cluster information.

What is RAID 5 or RAID 6 Erasure Coding

You can use RAID 5 or RAID 6 erasure coding to protect against data loss and increase storage efficiency. Erasure coding can provide the same level of data protection as mirroring (RAID 1), while using less storage capacity.

RAID-6

RAID 5 or RAID 6 erasure coding enables Virtual SAN to tolerate the failure of up to two capacity devices in the datastore. You can configure RAID 5 on all-flash clusters with four or more fault domains. You can configure RAID 5 or RAID 6 on all-flash clusters with six or more fault domains.

RAID 5 or RAID 6 erasure coding requires … Read The Rest ......

How to Disable Deduplication and Compression on vSAN Cluster

You can disable deduplication and compression on your Virtual SAN cluster. 

When deduplication and compression are disabled on the Virtual SAN cluster, the size of the used capacity in the cluster can expand (based on the deduplication ratio). Before you disable deduplication and compression, verify that the cluster has enough capacity to handle the size of the expanded data.

  1. Navigate to the Virtual SAN host cluster in the vSphere Web Client.
  2. Click the Configure tab.
  3. Under Virtual SAN, select General.
  4. In the Virtual SAN is turned ON pane, click the Edit button.
  5. Disable deduplication and compression.
    1. Set the
Read The Rest ......

How to Enable Deduplication and Compression on Existing Virtual SAN Cluster

You can enable deduplication and compression by editing configuration parameters on an existing Virtual SAN cluster.

Cloud storage concept

  1. Navigate to the Virtual SAN host cluster in the vSphere Web Client.
  2. Click the Configure tab.
  3. Under Virtual SAN, select General.
  4. In the Virtual SAN is turned ON pane, click the Edit button.
  5. Configure deduplication and compression.
    1. Set the disk claiming mode to Manual.
    2. Set deduplication and compression to Enabled.
    3. (Optional) : Enable reduced redundancy for your VMs.
    4. Click OK to save your configuration changes.

While enabling deduplication and compression, Virtual SAN changes disk format on each disk group of

Read The Rest ......

How to Enable Deduplication and Compression on a New Virtual SAN Cluster

You can enable deduplication and compression when you configure a new Virtual SAN all-flash cluster.

2-Pass-Post-Process-Dedupe

  1. Navigate to an existing cluster in the vSphere Web Client.
  2. Click the Configure tab.
  3. Under Virtual SAN, select General and click the Configure Virtual SAN button.
  4. Configure deduplication and compression on the cluster.
    1. On the Virtual SAN capabilites page, select the Enable check box under Deduplication and Compression.

      Disk Claiming automatically changes to Manual.

    2. (Optional) : Enable reduced redundancy for your VMs.

  5. On the Claim disks page, specify which disks to claim for the Virtual SAN cluster.
    1. Select a flash device to be used
Read The Rest ......

Design Considerations for Deduplication and Compression in vSAN Cluster

images

Consider these guidelines when you configure deduplication and compression in a Virtual SAN cluster.

  • Virtual SAN can eliminate duplicate data blocks within each disk group, but not across disk groups.

  • Capacity overhead for deduplication and compression is approximately five percent of total raw capacity.

  • Deduplication and compression are available only on all-flash disk groups.

  • On-disk format version 3.0 or later is required to support deduplication and compression.

  • You must have a valid license to enable deduplication and compression on a cluster.

  • You can enable deduplication and compression only if the storage-claiming method is set to manual. You can change the

Read The Rest ......

Managing Disks in vSAN cluster

Consider the following guidelines when managing disks in a cluster with deduplication and compression enabled.

  • Avoid adding disks to a disk group incrementally. For more efficient deduplication and compression, consider adding a new disk group to increase cluster storage capacity.

  • When you add a new disk group manually, add all of the capacity disks at the same time.

  • You cannot remove a single disk from a disk group. You must remove the entire disk group to make modifications.

  • A single disk failure causes the entire disk group to fail.

Verifying Space Savings from Deduplication and Compression

The amount of storage

Read The Rest ......

What is Deduplication and Compression

Pic-11

Virtual SAN can perform block-level deduplication and compression to save storage space. When you enable deduplication and compression on a Virtual SAN all-flash cluster, redundant data within each disk group is reduced.

Deduplication removes redundant data blocks, whereas compression removes additional redundant data within each data block. These techniques work together to reduce the amount of space required to store the data. Virtual SAN applies deduplication and then compression as it moves data from the cache tier to the capacity tier.

You can enable deduplication and compression as a cluster-wide setting, but they are applied on a disk group basis.

Read The Rest ......

VSAN Observer : Configuration and Management Step By Step – Part1

This is my First Post in VSAN performance monitoring Series . In this series we will learn how to setup and configure VSAN Observer for your VSAN Cluster.

What is VSAN Observer

VSAN Observer is designed to capture performance statistics for a Virtual SAN Cluster and provide access through a web browser and capture the statistics for customer use or for VMware Technical Support.

For any vSphere, Virtual SAN, and storage administrator wanting to dig deeper and analyze performance issues, the virtual SAN observer is a valuable tool. It provides an in-depth snapshot of IOPS, latencies at different layers of … Read The Rest ......