What's new in VMware VSAN 6.1?

By | September 13, 2015

Now during VMworld 2015 US, VMware announced Virtual SAN 6.1 with the following most important new features:

  • Virtual SAN Stretched Cluster - at last! With VSAN 6.1 you can build a stretched VMware cluster! The cluster can be spread across 2 sites with a witness (virtual appliance) at a 3rd site. This is really similar solution to a vSphere Metro Storage Cluster (vMSC) solution e.g. build on NetApp Clustered Data ONTAP, however VSAN is based on local/internal disks but NetApp, EMC are an external solutions.What's new in VMware VSAN 6.1 - Stretched Clusters There are some requirements: <=5ms RTT and bandwidth at least 10Gbit between site A and site B. Also L2 is necessary with Multicast. Between Witness VM and Site A or Site B: <= 100ms RTT, bandwidth at least 100Mbit and L3 without Multicast.
  • VSAN Replication with 5min RPO. vSphere Replication with Virtual SAN supports RPOs from 5 minutes to 24 hours. VMware Site Recovery Manager (SRM) can be used to deliver a fully orchestrated disaster recovery solution.What's new in VMware VSAN 6.1 - RPO 5min
  • Support for SMP-Fault Tolerance. VMware vSphere 6.0 introduced vSMP Fault Tolerance and it is supported on VSAN 6.1.What's new in VMware VSAN 6.1 - SMP FT support
  • Support for Microsoft Failover Clustering or Oracle RAC. Now, with VSAN 6.1, you will able to cluster Windows-based vCenter as well 🙂What's new in VMware VSAN 6.1 - cluster support
  • Virtual SAN for Remote Office and Branch Office (ROBO). Virtual SAN 6.1 provides the ability and support to deploy Virtual SAN clusters for ROBO scenarios. Some weeks ago I worked on a project where VSAN was not preferred because VSAN 6.0 requires at least 3 nodes. What's new in VMware VSAN 6.1 - ROBO

There are some others features as follows:

  • Virtual SAN Management Pack for vRealize Operations Manager (Global View, Health Monitoring and Availability, Performance Monitoring, Capacity Monitoring and planning).
  • New flash hardware support (DIMM-based SSDs and VMS SSDs). The first one is really interesting because lets connect flash storage to the memory channel via DIMM slots for very low (<5us) write latency.
  • Health Check includes some additional checks for stretched cluster (Witness host configuration, Network and Host Compatibility, Fault domain configuration).

For more information please follow VMware blog and Eric Siebert's post. Also I recommend Duncan Epping and Cormac Hogan book: Essential Virtual SAN (VSAN) Administrator's Guide to VMware Virtual SAN (VMware Press Technology).

Author: Mariusz

Architect (~ 15 years experience based on passion...) with strong background as a System Administrator and Engineer. Focused on Data Center Solutions: Virtualization/Cloud Computing and Storage/Backup Systems. Currently living in Poland.

6 thoughts on “What's new in VMware VSAN 6.1?

  1. Marco


    I read this article and both VPLEX and NetApp metro cluster but what is not clear to me is the physical connection.
    Two questions:
    1) VSAN and layer 2
    With VSAN, only L2 layer is required because there is not external storage to replicate and this is quite clear. But the question is:
    If I have correctly understood, usually sites are connected using fiber (that it is expensive) or MPLS (maybe with a 10gb link) but, in both cases, how the connections take place? Are there just routers or some specials network devices running special protocols? I read something about stretched cluster using OVT or dark fiber but I'm a bit confused
    2) Storage
    About VPLEX or NetApp metro cluster, what kind of PHYSICAL equipment is necessary to replicate storage? In the VPLEX article I saw that there are brocade fiber switch but how are they physically connected? Using fiber? Is there just a fiber cable between them? What kind of options are there?

    1. Mariusz Post author

      Hi Marco,

      1) VSAN replicates data via dedicated vmkernel(s) using multicast. L2 is spread between sites using DWDM devices and switches.
      2) Yes fiber and depending on distance, the fiber (or cable as you wrote 🙂 ) can be used to connect storages without FC switches or using FC switches.

  2. Marco


    still some of questions about this item:

    1) I just read something about DWDM and it seems the best technology to have <=5ms RTT. Do you confirm?
    2) Is possible to have VSAN using MPLS or not due to the high latency?
    3) When you did the project with NetApp or VPLEX, who configured the DWDM devices? You or the storage vendor?
    4) What do you mean with "...without FC switches or using FC switches"? Is there some device that translate fiber to Ethernet or something like this?

    1. Mariusz Post author


      1) yes
      2) no, VSAN stretched cluster (in this post) requires <=5ms RTT.
      3) Customer has already DWDM or needs to implement it by itself (telco provider).
      4) No - storage has HBA so you can connect them by fiber directly (= Storage A HBA--> Storage B HBA) and depends on distance it can be done with switch (= Storage A HBA--> Switch --> Storage B HBA).


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