Symantec ApplicationHA: High Availability for Virtualized Applications
How can you provide high availability to your virtualized mission-critical applications? There are several ways, and now Symantec is introducing a new option:
VMware’s HA provides restart-ability for VMs either running on a failed host, or VM’s that are completely unavailable (i.e. blue screen). While this will promptly restart the VM on a different host, you have still incurred some downtime. Furthermore this is done without any consideration to application integrity — HA’s job is simply to make sure that the VM is powered on.
VMware Fault Tolerance (FT) was introduced in vSphere 4.0 and allows for a passive clone of a VM to be in CPU lockstep with the active VM. In this scenario, the passive VM can take over in the event of a host server failure without missing a single CPU instruction. However, FT is currently limited to only supporting VM’s with one vCPU and snapshots are not supported which can pose challenges for backups.
Microsoft Cluster Server (MSCS) is another option, to provide HA for VM’s but this has drawbacks as well including some additional environmental configuration, and of course the licensing costs for the Enterprise version of Windows.
Symantec ApplicationHA could perhaps be described as the pairing of Veritas Cluster Server with VMware HA. Vertias Cluster server has been a leading clustering solution for many years with its excellent cross-platform support. Veritas Cluster Server uses a shared storage model to provide high availability as illustrated below:
Some may cringe when I say this, but at a very high level, MSCS are Veritas Cluster Server are similar — they both use a shared storage model, they both use a heartbeat channel and they are application aware. By integrating directly with the application and its logs, these solutions can provide strong HA support. But what makes Symantec ApplicationHA stand out is it’s integration with VMware HA and DRS as well as it’s integration with vCenter:
As illustrated above, the ApplicationHA management is done within the vCenter client itself utilizing a plugin. There is no need to use a separate tool to manage the application clustering — everything is available right from the vCenter client. And by integrating with VMware’s HA and DRS capabilities, ApplicationHA will be able to navigate the virtual infrastructure to configure the most optimal scenarios for high availability for applications.
ApplicationHA will support several applications, including Exchange, SQL, IIS, Oracle and SAP, and will include push capabilities for rapid deployment.
ApplicationHA is a very compelling solution for high availability and many will likely find it attractive at a list price of $350 (USD) per VM. I think that this is good market positioning by Symantec to leverage their proven Veritas Cluster technology with VMware integration and at an attractive price point. This also benefits VMware as organizations which previously resisted virtualizing mission-critical applications out of HA concerns, can take a closer look.