I had the pleasure of speaking at one of the breakout sessions at the DFW VMUG in Dallas, TX this past week.  To prepare I was able to talk to Cormac Hogan who is VMware’s Senior Technical Marketing Architect for VSAN.  Cormac is a wealth of knowledge so I also spent a lot of time absorbing the great articles in his blog http://cormachogan.com/ and his VSAN demos here.  Additionally I found good stuff on Duncan Epping’s http://www.yellow-bricks.com.  In 45 minutes I couldn’t do a deep dive so I had to stick to the highlights which I’ve listed below.  Bear in mind this is related to the VSAN beta that just recently went live.  If you haven’t already done so, sign up at http://vsanbeta.com/.

VSAN Highlights

  • vSphere 5.5 & vCenter 5.5 required – VSAN is built into vSphere & management is through the Web Client for vSphere 5.5.
  • Min 1 SSD & 1 HDD per host, Max 1 SSD & 6 HDD per disk group, Max 5 disk groups per host
  • Min 3 Hosts, Max 8 Hosts, Max 1 VSAN datastore per cluster (support for more hosts may increase in the future)
  • Max vsanDatastore = (8 hosts * 5 disk groups * 6 disks * size of disks) = 240 * size of disks
  • Capacity based on HDD only. SSD do not contribute towards capacity, used as read cache and write buffer
  • Can provision individual VMs with different profiles on the same VSAN datastore
  • Data stripes and copies can be anywhere in the cluster (no locality of reference)
  • SAS/SATA Raid Controller must work in “pass-thru” or “HBA” mode (no RAID)

VSAN Best Practices

  • Host Boot image: no stateless, preferred is to boot using SDcard/USB
  • SSD should be Min 10% of HDD Capacity (e.g. 1 GB of SSD to every 10 GB of SAS/SATA)
  • Disparate hardware configurations are supported but best practice is to use identical host hardware configurations (same #, capacity, performing disks)
  • Dedicated 10Gb (1GB is supported) network for VSAN. NIC team of 2 x 10Gb NICs for availability purposes
  • Not much sense to enable vSphere Flash Read Cache (VSAN uses SSD for cache)
  • VSAN VM Policy Management – Leave at default unless specific need to change
    • Number of Disk Stripes Per Object: Default = 1; Max = 12
    • Number of Failures To Tolerate: Default = 1; Max = 3
    • Object Space Reservation: Default = 0%, Maximum = 100%
    • Flash Read Cache Reservation: Default = 0%, Maximum = 100%
    • Force Provisioning: Default = Disabled

I hope this helps summarize what VSAN is all about.  I was excited to get many great questions from the audience and to see how excited they all were about VSAN.  I’m looking forward to how the Beta goes and how people like it!