My ramblings on the stuff that holds it all together
Long Distance vMotion… heading to the vCloud
VMware have an interesting proof of concept document posted online here, this is great progress for the platform and it can only be helped out by the close partnership with Cisco that has resulted in the NX1000V switch.
I’m no networking expert but to my understanding there are issues with extending Layer 2 networks across multiple physical locations that need to be resolved for this to be a safe configuration. to my limited understanding traditional technologies like spanning tree can present some challenges for inter-DC flat VLANs so they need to be designed carefully, maybe using MPLS as a more suitable inter-DC protocol.
The interesting part for me is that this will be the nirvana for VMware’s vCloud programme, where services can be migrated on/off-premise to/from 3rd party providers as required and without downtime. this is do-able now with some downtime via some careful planning and some tools but this proposition extends the vMotion zero downtime migration to vCloud.
As this technology and relevant VM/storage best-practice filters out of VMware and into service providers and customers this could become a supportable service offering for vCloud Service Providers.
To achieve this you still need storage access from both sites, to me the next logical step is to combine vMotion and FT technologies with some kind of host based replication or storage virtualization like the Datacore products. this will remove the dependency (and thus potential SPOF) on a single storage device for vMotion/FT.
Virtualizing/replicating the actual VM storage between different arrays and storage types (EMC—>HP, or even DAS—>EMC) and allowing (encapsulating) it over standard IP links rather than relying on complicated and proprietary array based replication and dedicated fibre connectivity is going to be a key success factor for vCloud, it’s interesting to see all the recent work on formalising FCoE along with other WAN-capable standards like iSCSI.
Some further reading on how I see “the cloud” evolving at a more practical level here