Enabling vSAN Space Efficiency Features in All-Flash Systems

Your Cloud Foundation system might be an all-flash storage environment. For all-flash storage, the software stack's vSAN space efficiency features enable you to reduce the amount of space for storing data in your workload domains.

As provided by the vSAN features installed in an all-flash environment, you can use these techniques to reduce the total storage capacity required to meet the needs in your workload domains:

• You can enable deduplication and compression on a workload domain's underlying vSAN environment to eliminate duplicate data and reduce the amount of space needed to store data.

• RAID 5 or RAID 6 erasure coding is a policy attribute in a workload domain's vSAN policy. Erasure coding can protect your data while using less storage space than the default RAID 1 mirroring. You set the Failure tolerance method in the vSAN policy to enable these features.

For detailed information about these vSAN space efficiency features, see the vSAN documentation at https://docs.vmware.com/en/VMware-vSphere/6.0/com.vmware.vsphere.virtualsan.doc/GUID-0D43429F-E2E7-4647-8ECA-8F606E9E910F.html. Specific topics about these features include:

• Using Deduplication and Compression topic: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.virtualsan.doc/GUID-3D2D80CC-444E-454E-9B8B-25C3F620EFED.html

• Deduplication and Compression Design Considerations topic: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.virtualsan.doc/GUID-2285B446-46BF-429C-A1E7-BEE276ED40F7.html

• Using RAID 5 or RAID 6 Erasure Coding topic: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.virtualsan.doc/GUID-AD408FA8-5898-4541-9F82-FE72E6CD6227.html. As described in that topic, RAID 5 or RAID 6 erasure coding enables vSAN to tolerate the failure of up to two capacity devices in the datastore. You can configure RAID 5 on all-flash vSAN environments having four or more fault domains. You can configure RAID 5 or RAID 6 on all-flash vSAN environments having six or more fault domains.

• RAID 5 or RAID 6 Design Considerations: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.virtualsan.doc/GUID-6D818555-8DE8-4F06-9498-66903FB9C775.html

• The Edit vSAN Settings topic includes the detailed steps for enabling deduplication and compression: https://docs.vmware.com/en/VMware-vSphere/6.5/com.vmware.vsphere.virtualsan.doc/GUID-FF1AE93F-817A-4894-9A38-EB474AA754F1.html

You enable these features on a workload domain's underlying environment by using the vSphere Web Client to edit the vSAN settings.

Prerequisites

Enable the deduplication and compression features on a workload domain after the workload domain creation process is successfully completed.

Procedure

1. Navigate to the workload domain's virtual environment in the vSphere Web Client using the vCenter launch link on the workload domain's details page.
2. Enable deduplication and compression by editing the vSAN settings using the Manage tab and the general settings for vSAN.

   Set the Add disks to storage to Manual to access the deduplication and compression setting.

   When you save your edits in the vSAN settings to enable deduplication and compression, vSAN will automatically upgrade the on-disk format, causing a rolling reformat of every disk group in the vSAN environment. Wait until this process is completed before making additional changes to the workload domain.

3. (Optional) Enable RAID 5 or RAID 6 erasure coding.

   • To use RAID 5, navigate to the vSAN storage policy and edit it to set Failure tolerance method to RAID-5/6 (Erasure Coding) - Capacity and Number of failures to tolerate to 1.

   • To use RAID 6, navigate to the vSAN storage policy and edit it to set Failure tolerance method to RAID-5/6 (Erasure Coding) - Capacity and Number of failures to tolerate to 2.

   As described in the vSphere Product Documentation's Using RAID 5 or RAID 6 Erasure Coding topic, RAID 5 and RAID 6 erasure codings do not support a Number of failures to tolerate value of 3.