--On March 12, 2009 1:31:55 PM -0700 Seth Mattinen <sethm@rollernet.us> wrote:
Thomas Goirand wrote:Marc Aymerich wrote:Hi Thomas! Thanks for your recommendation. We have considered using DTC control panel in our servers, but the structure of DTC is not compatible with our system. We have 3 virtualized servers, for web, mail and mysql, each of this servers mounts a different disk partition from a SAN server, and DTC stores web and mail in the user home directory, so we have no idea how to adapt this to our needs.I see absolutely no reasons why you would separate in 3 servers if they are all visualized. If you do that, that is because you don't have enough resources on ONE server, there is no reason otherwise.There are plenty of reasons for ensuring, for example, something doesn't walk all over MySQL or a mail flood doesn't eat up all the resources and take the website down. Especially if user shell account are permitted on the web server.
And virtualization doesn't really solve this. There's no virtualization system that allows you to set QoS on Disk I/O and most of the time, when a server starts to pop, it's Disk I/O nowadays. That's not to say that it ALWAYS is, but a LOT of the time it is. Now Virtualization in concert with dedicated disk pools can, assumign your virtualization allows you to keep the virtualized machines from interfering with eachother in other ways (Network, CPU, and Memory resources for example)
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