Changes with Device Claiming Options in vSAN 6.6

vSAN 6.6 introduced several advancements that focused on ease of use. Easy Install, Configuration Assist, and pro-active cloud analytics are great examples of features that simplify the deployment and administration of vSAN. The positive feedback from these enhancements has been incredibly strong, and is part of an ongoing effort to make vSAN easy and flexible to deploy and operate.

Simplicity is not only about reducing the number of steps needed for a task, but also ensuring a desired outcome based on the intentions of the user. vSAN has always offered a lot of flexibility in the design and arrangement of disk groups on hosts that contribute to a vSAN datastore. Prior to vSAN 6.6, the process of claiming disks could be achieved by one of two modes: “automatic” and “manual.” vSAN would default to “automatic” mode, and made assumptions about the intent of each device as it completed the creation of the disk group. In hybrid configurations, this made some sense in part because vSAN could only present spinning disks as capacity, and flash devices as caching.   Two trends in the industry have occurred since the original approach to claiming disks was devised.

  • All-flash vSAN clusters have quickly become the most common deployment configuration. Hosts might have a collection of flash devices, but the original “automatic” claiming process did not let the user provide input to determine the desired use of these devices, such as their assignment to cache or capacity, and arrangement of disk groups.
  • A growing popularity of new chassis with large numbers of drive bays. Due in part to its integration into the hypervisor, vSAN’s efficiency in delivering I/O allows it to easily take advantage of these new chassis form factors. This allows users to easily scale up storage capacity and performance of a host using more disks, and multiple disk groups. As a result of these chassis designs, an administrator may be more inclined to have a predetermined configuration of disk groups that the “automatic” claiming mode could not account for.

Due to these changes in typical server deployments, vSAN 6.6 focuses on a guided approach for claiming devices to better accommodate the considerations above. Since the “automatic” mode no longer represented the common configurations or needs of the user, it was removed in favor of a more intelligent, guided approach to claiming devices.   There are two ways of claiming devices in vSAN 6.6. The guided approach can be achieved by navigating to the vSAN cluster desired, clicking on Configure > vSAN > Disk Management, and clicking on “Claim Disks.” An alternate method of claiming devices can be performed by clicking on Configure > vSAN > Disk Management, selecting a host, and clicking “Create a new disk group.” Figure 1 shows where the two options are available.

Figure 1. Device claiming options in “Disk Management”  


Let’s look at what the guided claiming process looks like with all-flash based hosts. In the images below, we have two hosts recently added to a vSAN cluster. By clicking on “Claim disks” as shown in Figure 1, we are presented with a list of unclaimed devices on all available hosts in the cluster. They will be arranged by disk model and size, but this can also be arranged by host. In this case, vSAN will identify the device type (flash, or spinning disk) but give you the option to mark it differently should it be recognized incorrectly. Figure 2 shows the devices ready to be claimed, and predicting what they will be used for, yet leaving the ability to change their intended purpose. You may also wish to not claim specific devices at this time.

Figure 2. Claiming disks workflow  


Once the OK button is clicked the newly claimed devices will create disk groups on the respective hosts, as shown in Figure 3.

Figure 3. Device claiming completed, and disk groups created  


As you can see, this approach guides you through the selection process with a semi-automated approach, yet provides flexibility to allow you to assign the devices in a manner you desire.   We believe the guided process of claiming devices in vSAN is a smarter approach for the consistent, uniform configuration of disk groups across all hosts in a vSAN cluster, and we hope you will too.



Leave a Reply

Your email address will not be published.