We are at the stage, finally, where we are prepared to deploy public facing VM guests. Now we have to answer these questions: How many guests in total should we contemplate and what services are placed on which guests?
My question comes down to whether it is considered advisable to run the primary DNS and IMAP, or indeed all services, on separate vm guests; or should we continue, more or less, with the present split and just move everything into guests on a one-for-one basis from our existing hosts? Will additional vms necessarily increase the amount of time given to system maintenance as I suspect?
Previously, with only a few physical hosts, the number of platforms was fixed and services were split more or less on the basis of internal and external users. Not to mention which host had more available resources at the time the service was implemented.
For example, presently our primary DNS and the IMAP services runs on one server with MailScanner controlled Sendmail used only for local delivery and forwarding. On another host we run the publicly accessible MX MTA and a secondary public DNS. On a third we run our fax server and public web site together with a caching only DNS service.
I very much would appreciate any relevant comments from people who have already resolved this matter together with their reasoning.