TBL Networks, The Blinky Light

This is the Live Blog of INF-BCO2655 – VMware vSphere Fault Tolerance for Multiprocessor Virtual Machines – Technical Preview. You’ll find my recap of the session below.

Speakers:

• Jim Chow – VMware, Inc. Staff Engineer
• Srinivas Kotamraju – VMware, Inc. Product Manager
• Shrinand Javadekar – VMware, Inc. Senior MTS

Shrinand Javadekar has taken the stage and is discussing vSphere availability features to date (NIC-Teaming, HA, DRS, vMotion, storage multipathing, etc.). This session will concentrate on continuous availability with Fault Tolerance.

He goes on to define continuous availability

• Zero downtime
• Zero data loss
• No loss of TCP connections
• Completely transparent to guest software

One of the major limitations of Fault Tolerance as it exists today is the fact that FT can only protect uni-processor VMs. VMware has reached a key milestone in solving this and this is what is being shared in this session. First, some background.

A technology called vLockstep keeps the primary and secondary VM in sync. The data exchange happens over the FT Logging network (dedicated 1Gb networks). The FT protected VM and the secondary VM use shared VMDKs. VMware is replacing vLockstep with the SMP FT protocol. Here are some of the design points:

• Dedicated 10GbE for FT logging
• Each VM (primary and secondary) has its own VMDKs

Jim Chow has taken the stage and will be discussing SMP FT in practice. The following is the proposed workflow.

• Turn on FT (creates 2 VMs – the secondary is an exact clone)
• The opportunity to separate the primary and secondary VMs on multiple datastores allows greater availability
• A single datastore (called the Break Datastore) must be provisioned in case the FT logging link fails. The secondary mode of communication happens through the tie break (Break) datastore.
• When you turn on FT for a VM you need to select the initial placement of the secondary VM. The two hosts must be vMotion compatible.
• Next, you have the opportunity to choose the datastores that the secondary VM and its VMDKs will reside on.
• Finally, you will click Finish on the “Ready to Complete” screen.

Next, the live demo will show a virtual vCenter (4 vCPU, 16GB RAM) server protected by FT failing over. It worked as expected. The proposed SMP FT will allow vStorage APIs for Data Protection (VADP) to create non-disruptive snapshots on virtual machines protected by FT.

This is clearly a step in the right direction and I cannot wait until this is available for our clients. Thank you for reading.