VM /ETC

I attended this VMworld 2008 session on Wednesday 09.18 at 9:00 AM. The presenter was Sunder Parameswaran who is a Senior Product Manager at Symantec. The session was about using Veritas Cluster Server (VCS) in VMware virtual infrastructure (VI) to overcome application high availability and disaster recovery (DR) challenges.

My main interest in this session was on the topic of Geo Clustering with VCS. Also known as Metro Clustering, this is the ability to have one node of the cluster at your primary data center location and the second node at a separate physical location like a disaster recovery site.

Sunder began by outlining various VI challenges.

• Need for heterogeneous management of mission critical applications in both physical and virtual
  servers.

  • VI makes management more complex because a distinct set of tools is used today for both physical and virtual systems

• VI creates a larger emphasis for handling unplanned downtime and DR

With over companies using VCS for over 10 years in the field, VCS provides the following features to meet
these challenges:

• Can manage mixed physical and virtual environments

• can manage various server operating systems

  • solaris

  • aix

  • linux

  • windows

  • VMware

Next Sunder talked specifically about how VCS provides application aware high availability for VMware above
and beyond VI Enterprise HA features of an ESX Cluster. The session discussion also covered VM application clustering advantages unique from Microsoft’s clustering (MSCS)

• VCS can monitor and fail over several mission critical applications such as Exchange, SQL, Oracle,
  and SAP

• There is no need for passive standby hardware

• Requires agents in the server OS

• provides DR ability to cluster between physical data center locations

Geo Clusters (Metro Clusters) with VCS

• Requires synchronis replication between 2 sites within 80 km of each other

• It is directly effected by the link latency and the quality of the replication technology

• single click cluster configuration that is completely automated.

• can handle split brain network scenarios

Global DR with VCS

• VCS Firedrill provides zero downtime testing of DR plans

• requires array based replication

• leverages storage snapshots of thefiler at the DR site

• can be scheduled (example of DR testing every month)

• provides network isolation of DR test servers

• Is not fault tolerant and client will notice downtime

VMware HA versus VCS

• VCS protets against application crashes where HA watches for ESX or VM crashes

• VCS can control the specific start up order order

• VCS protects against admin errors in the VM configuration.

  • Configuration changes

  • admin error

  • Server NIC failure (not usually a problem in VMs, but possible)

• VCS protects against storage connectivity failures

VCS Compatibility

• VCS is not supported in ESX version 2.5.x or earlier

• VCS is certified with various SAN vendor replication technologies

  • HDS Truecopy / Universal

  • EMC SRDF

  • IBM Metromirror

  • HP EVA is on the roadmap

  • NetApp Snap Mirror is on the roadmap

• VCS Application support

  • IIS

  • SQL 2005 and 2005

  • Apache

  • Linux

  • Oracle 10g

  • SAP

  • Exchage 2003 and 2007

  • Websphere

  • Sharepoint

  • Weblogic on Linux

  • Framework to customize for any application

  • is not supported / can not use or combine with MSCS

VCS Considerations for VMware Vmotion, DRS, and HA

• Considered by Symantec as complimentary solutions

• Postion VCS for applications and scenarios where Vmotion and DRS do not cover availability needs.

• VMware HA is power off crash consistent fail over and VCS is clustered fail over

  • recommendation is to disable VMware HA when using VCS

• VCS installs agents on each ESX host. State of each host is known by other hosts

Protecting VirtualCenter Server with VCS

• Discussion was focused on VC as a VM, but I imagine this applies to physical VCs as well

• Has additional logic to auto reconnect ESX hosts after fail over to second node

• • Same goes for Geo Clustering of VC (Metro Clustering)

VCS Futures

• Future VCS ESX installations will utilize VIMA. It will be optional whether using a dedicatd VIMA or a
  shared VIMA

• Prioritized applications – the ability to give priority to specific application fail overs

• browser based management

• enable active server provisioning based on workload

• multi tier application control and support

There are currently 2 licensing models for VCS. You can purchase licensing by number of VMs or by the ESX
CPU.

virtualization, vmware, veritas, vcs

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