VMworld 2013: VMware Virtual SAN #STO5391

Before going into detail about this session, I must say that the speakers were hard to understand due to bad English pronouncement. It would be good if the speakers would train this so that everybody can understand what they are saying.

This session, primarily presented by Christos Karamanolis was all about VSAN, or Virtual SAN, the new feature available from vSphere 5.5.

In my opinion, VSAN is a replacement for the Virtual Storage Appliance (VSA) released during vSphere 5.0. And, VSAN could compete with the solution offered by Nutanix, except the intelligent software that Nutanix has developed will be more enhanced compared to VSAN.

For people not familiar with VSA; this solution will transform the local storage in your ESXi host to a VSA datastore. With a minimum of 2, maximum of 3 ESXi hosts, you can create a VSA cluster. Hosts in this cluster will replicate their VSA datastore with adjacent ESXi hosts and provide high availability (and stable performance, since it’s local storage!). You can run the VSA datastore next to your other datastore and will be able to storage vMotion between datastore types.

VSAN is enabled on ESXi cluster-level and will by default initialize all unused space on the hosts in this cluster. Advanced configuration enables an administrator to only use a specific amount or type of storage capacity. You don’t need to deploy extra VMs or vApps to use VSAN. It’s all inside vSphere 5.5.

Hardware-based (or software) RAID will not be used, but replication will be used instead. For each VM it’s possible to define how many replicas will be available using storage profiles in vSphere. This way you can protect important VMs using more replicas and provide a simple protection for the less important VMs.

Replication will keep copies of the VMDK blocks among all ESXi hosts in the VSAN-enabled cluster and removes the need for a RAID configuration. The local initialized storage (SATA, SAS or SSD drives) will be added to one big datastore presented by VSAN. This datastore will grow in size as you add extra drives. You don’t need to keep all your hosts the same, you can add extra SSD or HDD drives to specific hosts to add extra capacity of a certain drive type. The same goes for compute, but you need to have a minimum of 1 HDD and 1 SSD drive in a host to enable VSAN. A minimum of 3 vSphere ESXi 5.5 hosts are required to enable VSAN at cluster level.

The ESXi hosts need to have a 1GB or 10GB NIC and need to have VSAN virtual networks configured in order for VSAN to be enabled and be operational. When you have a RAID controller in your host, configure it as JBOD. As stated earlier, you should not configure RAID protection in combination with VSAN.

The vSphere hosts need to be on the VMware HCL to be supported for VSAN use. Of course all of your hardware is listed on the HCL.. Right? 🙂

When using replicas, write I/O will go to all replicas for that specific VM. Read I/O will go to any replica. This way of I/O pathing will provide high performance and high availability.

One last thing I would like to mention is that VSAN provides a detailed performance view which can be used for capacity management and troubleshooting.

When vSphere 5.5 is available for download I will most certainly test out the VSAN functionality and see if it can indeed replace the VSA functionality.

Deploying vSphere Storage Appliance 5.1 headaches

I have spent a full day deploying VSA 5.1 for the first time because of a lack of experience with the product and in my opinion some missing “Pay attention to:” items in the installation and configuration documentation.

My setup: two HP ProLiant Gen8 ESXi hosts running on vSphere 5.1 U1, both a RAID1 logical disk of 146 GB and a RAID5 logical disk of about 2.2 TB.
ESXi was installed on the RAID1 disk and the 2.2TB disk was meant for installing VSA.

I started with downloading the VSA binaries, including the VSA Manager. Ran the setup on the vCenter Server and after a while I got myself a nice VSA Manager tab in the vSphere Client. Using the wizard that popped up, I was on my way configuring VSA the way I wanted to.

As I only had two ESXi hosts, I required a third cluster member for maintaning quorum. This is done thru the VSA Cluster Service which can be installed on Windows or Linux. Or if you have three VSA hosts, you don’t need the cluster service at all.

But; before I rush to the climax: when I came to the point that the wizard was asking me how much capacity to reserve for the VSA datastores, it only showed me 146GB! What the…?

I tried several things: rebooting the ESXi hosts, restarting the vCenter Server, deleting the datastores I provisioned on the 2.2TB logical disks, creating a smaller datastore. Nothing was bringing me close to finding my missing capacity. I started Google’ing “VSA missing capacity”, “VSA multiple datastores”, “VSA not showing datastore” and so on. After some searches I found information stating that the smallest capacity counted. I rechecked the manual for this and indeed, it stated the same: Lowest capacity wins, make sure your datastores are of equal size.

Finally, I emptied the small datastores by migrating the VMs off. Unmounted the datastores and removed it using the vSphere Client. After running the VSA Manager wizard again, it finally showed me my rock-hard RAW capacity, Hoorah!

After deploying the whole thing, I recreated the small datastore for the sake of it and everything was working the way I wanted it to do in the first place.

Some remarks:

  • When deploying VSA, make sure only the datastore you want to include in VSA is active, or as the documentation states, multiple datastores of the same size. I guess if I would’ve installed ESXi on a flash drive and utilize all disks into one datastore, I would have been done with the job in less then 2 hours.
  • The vSphere Feature IP is the VSA-VMotion portgroup (which you should not create as VM portgroup, but as VMkernel Portgroup)
  • Preconfigure the portgroups needed for deployment on each ESXi host participating in your VSA cluster: VSA-VMotion, VSA-Back End, VSA-Front End, Management Network and VM Network. The names are case sensitive.
  • Install the VSA Cluster Service if you need it (two VSA hosts instead of three) before running the wizard.
  • Expanding your VSA capacity is a piece of cake!
  • Migrating VMs from your local datastore to the VSA requires VMotion. VMotion is not available in vSphere Essentials Plus. So deploy all your products within the 60 day evaluation period, or apply a test license for vSphere Enterprise Plus and vCenter Standard like I did and remove it after deployment.
  • RTFM (Read The Fucking Manual) but still; I think more guidance is needed in the documentation for people with no VSA experience.

Thanks for reading!