Chris's Wiki :: blog/tech/ExpensiveVirtualization Commentshttps://utcc.utoronto.ca/~cks/space/blog/tech/ExpensiveVirtualization?atomcommentsDWiki2008-06-21T13:31:16ZRecent comments in Chris's Wiki :: blog/tech/ExpensiveVirtualization.From 71.65.56.124 on /blog/tech/ExpensiveVirtualizationtag:CSpace:blog/tech/ExpensiveVirtualization:9d322b2038f40326943461b4f41245182dda6bd1From 71.65.56.124<div class="wikitext"><p>You're right, in that the idea of virtualization is a tradeoff. </p>
<p>For example, I just built my infrastructure using a blade enclosure of 10 servers. I could have done the same thing with 2 extra large machines in a high-availability failover setup with ESX. Because I'm only dealing with 10 physical machines, it wouldn't be worth the tradeoff. If I scaled that up an order of magnitude and had the option of building 100 blades or 20 high-availability ESX machines, the extra cost of ESX is such a smaller percentage that it pays me to only have the 20 servers. </p>
<p>Due to the relative higher cost of the 20 large servers, they're highly redundant and less likely to go down due to transient infrastructure issues. You're also more likely to have redundant, well, everything, if you're spending the sort of money to get an infrastructure of servers like that. </p>
<p>After researching it for several months, I'm convinced that in the right infrastructure, Virtualization can have a much higher uptime than a lot of enterprise-level individual server implementations. It's just not for everyone, due to the extra cost of the HA virtualization environment. </p>
<p>--Matt<br>
<a href="http://standalone-sysadmin.blogspot.com">http://standalone-sysadmin.blogspot.com</a></p>
</div>2008-06-21T13:31:16ZBy Chris Siebenmann on /blog/tech/ExpensiveVirtualizationtag:CSpace:blog/tech/ExpensiveVirtualization:f137f593b6e678eb477132c1cdd8a04df45bf988Chris Siebenmann<div class="wikitext"><p>I don't think any HA mode can eliminate the need for multiple relatively
powerful servers, although with extra software and disk space you might
be able to get away from the need for some sort of SAN itself.</p>
<p>(You need relatively powerful host machines because you need to be able
to run all of your virtual machines after you lose one host. This implies
that each host has to be over-configured for its usual load, so that
after you lose one machine your remaining pool of hosts can take over
the orphaned virtual machines without dying.)</p>
<p>To put it another way: if you're getting into virtualization for anything
important, you can't just use some existing spare servers you happen
to have lying around; you're going to have to build a real environment
for the purpose, which costs a not insignificant amount of money. (And
it costs more if you have to pay license fees for things like ESX HA
support.)</p>
</div>2008-06-20T17:12:04ZFrom 71.91.135.9 on /blog/tech/ExpensiveVirtualizationtag:CSpace:blog/tech/ExpensiveVirtualization:5a95ee2fd7d9f9e9b199a3e5f80b3d9571b1a51aFrom 71.91.135.9<div class="wikitext"><p>Have you ever run ESX or Xen in HA modes? Your whole argument goes out the window.</p>
</div>2008-06-20T13:09:07Z