It's probably 99%
There's little that can't run just as happily on another GNU/Linux\r\ndistro as Red Hat. Particularly if you hold yourself to standard\r\nservices: file, print, mail, web (:80 or :443), DNS, VPN, databases,\r\netc. There's no need to look outside a standard distro for any of\r\nthis.
\r\n\r\nWhere there is an application which specifies itself to be\r\n"Red Hat only":
\r\n\r\n- \r\n
- Watch out. "Only runs on..." is code for "we don't honor open\r\nstandards or test in wide environments". Such applications often lead\r\nto problems down the road in upgrading or modifying the base system.\r\nYou're better off elsewhere. \r\n\r\n
- In all likelihood, it will run without trouble on another\r\ndistribution. \r\n\r\n
- If tweakage is required, for major applications (Oracle,\r\nSAS, etc.), you'll likely find copious and detailed notes on deployment\r\non other platforms. \r\n\r\n
- LSB ensures that there is a flat base for all GNU/Linux\r\ndistros. Debian isn't currently certified, but it's very (or fully)\r\ncompliant with the lsb package. Again, if the vendor is\r\nbuilding to standards (and they damned well should), operating under\r\nanother environment shouldn't be an issue. \r\n\r\n
- It's possible (and perhaps advisable) to set up an RH-only\r\nenvironment for specific critical apps. Frankly I'd suspect this to be\r\nmore likely the case with large firms (who can throw a few hundred grand\r\non a problem) more than your posited small business. There are also\r\nways to do this, via chroot and uml, without additional HW expenditure.\r\nThis also provides the benefit of shielding the RH system behind a more\r\nreadily secured alternative. \r\n\r\n
- "Supported" is code for "we'll offset some of your costs". My\r\nexperience with RH and Debian is that I would spend far more time\r\nwrestling with all other aspects of a RH distro than I would benefit\r\nfrom the "it just works" aspect of Debian, even with the additional cost\r\nof managing an additional package myself. From a total cost standpoint,\r\nDebian wins. Your clients might or might not realize this, I would\r\nstructure my own rates to reflect this fact though. \r\n\r\n
I can understand vendors wanting to restrict their support costs. I\r\nthink the vendor-specific distro support thing is ultimately\r\nshortsighted. It will cost marketshare.
\r\n