Oct 25 2008

Wholesale High Availability

Alan just coined WholeSale HA. The idea of rebooting a whole virtual machine rather than just failing over 1 service.

He wants to have the best of both worlds in 1 framework, he however doesn't specify what parts he likes from the WholeSale HA setup

Yes you want to use it coupled with hardware predictive failure analysis tools. In order to achieve Higher Availabilty, but I don't think the WholeSale HA part is real HA.

WholeSale HA isn't going to be fast enough for most of the business critical environments.
You simply cannot afford to reboot or even boot a full machine and the related downtime that brings for your service.

So yes a best effort combination, but with a strong focus on the application state would be preferred. WholeSale is a good start .. but it's definitely not where you want to stop.

Dec 17 2007

Integrating HA and Virtualization

Alan Robertson is discussing how Managed Virtualization (including HA) conflicts with System Management

He has some interesting points regarding managing infrastructure , in his vision there are just too much layers that don't talk to eachother .
He also points out some of the issues with CIM and SNMP .

Alan thinks the ideal way to go is to have your HA solution manage your Virtualization also.

I`m wondering if this doesn't add too much complexity.

If you are already making sure the services in your virtual machines are highly available, then why would you want to add another layer of complexity ? Surely the idea of being able to migrate virtual machines around sounds tempting but do we really need that extra layer of complexity ?

I've explained that migrating a virtual machine to another server won't help you when your apps crash or when your physical server fails.

But keeping an overview of which services are running where from 1 place seems like an interesting idea.

I've been tinkering about using the resource concept of Linux-HA however to serve another purpose than pure high availability. You might want to use its constraints to define how many virtual machines should run on and how much resources they can use on a certain physical machine. Hence create a loadbalancing infrastructure with it.

(I`m really really hoping someone now replies to this with a url which gives me a HAResource that does Live Migration :))