One of the coolest (and most dangerous) commands in vSAN is objtool. Since this datastore is not vmfs but vsanfs (and object based), the objtool command is the utility that performs different tasks such as creating, resizing and deleting objects.
What follows is a series of examples on how to use such command:
Object path: /vmfs/volumes/vsan:521305e4430dd845-d59b1943736fdc88/
And how do I create an object?
# /usr/lib/vmware/osfs/bin/objtool create -s 1KB -a 3 -n javierobject Creating object of size 1024 bytes Setting object class to 0 UUID:3184dd59-c0ea-6ab8-b241-005056013df7how do I create my own object?
Note: The previous command creates an object using the default policy. This could be verified also with the rvc.
Note: Add the -t 3 option to the previous command to create a vmswap object. This can also be verified with the rvc.
Creating and removing directories in a vSAN datastore is not as simple as using mkdir and rmdir or rm -rf because the vSAN datastore is object based. In order to do that, special vSAN related commands exist to perform such tasks.
Notice what happens if you try to use the mkdir command:
# cd /vmfs/volumes/vsanDatastore
# mkdir testdir
mkdir: can't create directory 'testdir': Function not implemented
The commands that follow perform the same tasks as the icon with the green plus sign on the web client. These commands should be used if the vCenter server is not available.
How to do it: Step 1: Access the folder that contains the utilities
# cd /usr/lib/vmware/osfs/bin
Step 2: List the contents of that directory
objtool osfs-ls osfs-mkdir osfs-rmdir osfsd
Step 3: Verify that a directory called testdir does not exist
# ls -lh /vmfs/volumes/vsanDatastore/testdir
ls: /vmfs/volumes/vsanDatastore/testdir: No such file or directory
Step 1: Select your vCenter Server, click on Configure, select Key Management Servers and click on the Green Plus Sign. Specify the name of the KMS cluster, the IP address and a port to use. Currently, there are two supported KMS Servers (Hytrust and EMC). The KMS servers need to be KMIP 1.1 compliant.
Step 2: You will have to establish a trust relationship with the KMS server. Since different KMS servers are supported, you will have to select the type of certificate to download. Different choices are available.
Step 3: Verify that the connection state is Normal and that the procedure succeeded.
Step 4: Select your vSAN cluster, click on Configure, select General and click on Edit. Enable Encryption. The KMS related information should be automatically populated. Click on OK.
Step 5: Once you enable Encryption, every disk will be reformatted. This process will take time. The amount of time will depend on how many drives need to be formatted and the size of the drives.
Once this is done, the entire datastore is encrypted. Encryption works with both the hybrid solution as well as the all-flash. If new servers are added to the cluster, the disk groups created on the new host will be formatted to support encryption.
One of the many tools available for testing Virtual SAN is a buried python script called vsan.DiskFaultInjection.pyc. Located in the /usr/lib/vmware/vsan/bin directory, this utility can generate permanent or transient errors. Furthermore, it can emulate unplugging of disks.
Using the -h option (for help), an administrator can see the options available for this command. Only to be used pre-production, this script can generate failures to allow the user to understand what happens in such cases.
Below is an example of what happens when a capacity disk is affected by such permanent failure. In the case of a raid5 virtual machine, the virtual machine would continue to run. If enough servers and/or disks are available, the rebuilding of the date would take place immediately. The -p option is used for permanent errors and the -u option to unplug a disk.
Errors would be seen everywhere, notice the capture below.
The -c (clear option) is used to remove the permanent error. If using the -u option, simply rescan the storage via esxcfg-rescan -A.
Virtual SAN 6.6 introduces a graphical method to install a vCenter appliance on a freshly installed esxi host in order to eventually install and configure v vSAN cluster. The required software versions are: ESXi 5310538 , VC 5318154
As you start a fresh install, notice that the latest version of vSphere 6.5 introduces a new option that allows to "Install on a new Virtual SAN cluster containing the target host". Proceed with a normal installation.
Select the vCenter option with the embedded PSC.
Select the esxi host that will host the new vCenter appliance.
Name the appliance and provide the root password.
Here is where you see the big difference. Notice the option at the end. Select it.
Name your future datacenter and cluster.
Specify which drives will be used for the Virtual SAN datastore. Indicate which drives will be used for cache and capacity.
The rest is pretty much the same, provide the network related information and continue as usual.
Once the installation is done, the administrator can verify that the vCenter is in working order.
Once the vCenter appliance is running, log in, create the vmkernel port for Virtual SAN on that node and proceed as usual. Add the remaining servers and their vsan ip addresses and you are done.
Some people mistakenly look at tools inside of a guest operating system (for example, the task manager) and when faced with 100% cpu utilization, they automatically believe that such virtual machine needs more vcpus. Not necessarily. You really need to look at what is taken place on the host and compare the results. Remember that the guest OS is not aware of what is actually happening on the host.
Notice that this case this virtual machine running Windows displays 100% cpu utilization.
However, notice that the esxi host does not have any of the logical cpus at 100% and that virtual machine is NOT using 100% of the actual lcpu (core). Notice the %MLMTD column and %RDY.
In this case, the reason is due to a cpu limit. Notice the capture below. This virtual machine has the limit set to 50% of the maximum number of cpu mhz. Yet, the guest OS is not aware of this.
Installing esxi to a usb device is simple, just insert a cd and during the installation point to a usb device. This shows how to prepare a bootable usb device that allows you to install esxi onto any type of device.
Step 1: Launch your browser and point to https://unetbootin.github.io/
Step 2: Download and launch unetbootin. Point to your .iso image and click OK.
Step 3: Click on Exit.
Step 4: Verify the contents of your USB drive.
Step 5: Boot your future esxi host from USB and start the installation.