I'll start with the second part first, and even with a rant, at that: VMWare doesn't work for Linux. If you put a Linux system on a heavily used VMWare box, VMWare can't complete the Linux I/O quickly enough, Linux detects the timeout, and places the filesystem in a read-only state. There is no solution if you want to stay within your standard Linux distribution. VMWare does have a disk driver that is supposed to work, but the only change is that they greatly increased the disk I/O timeout, and installing it means headaches when you later want to apply maintenance to your Linux system.
Then to the actual question: The appliance mode works well, if you never plan to upgrade it, or it is a stand-alone application unto itself, with little outside information applied or kept. When the time comes to upgrade, you have to figure out what to take from the old system, and what you don't want to take for fear of overwriting something new and important in the new system. And now, the "it depends" part: One server, one function is much more a political battle than a technical one. On Windows, where there is no concept of a "User", and therefore no concept of security, you're forced into the one server, one function mode of implementation, in order to keep prying eyes out of each other's applications and data. But on Linux, whatever platform you're on, this isn't the case. You can easily implement multiple user groups and applications on a single Linux image and still isolate one from another. The problem comes when those groups find out that they're sharing the system, and don't feel that you've applied the correct priority, and security to their project. Most things are implemented in separate Linux systems because it is politically easier to explain the application's level of isolation if you can draw a line around the application and say "This is your box". When there are other things within the line, people get nervous, especially the ones used to Windows. The downside of this in a virtual environment is that you are repeatedly implementing the same operating system code in memory for each unique image, when in fact, this code could have been shared by several individual applications, were they to share a single Linux image. It would be more efficient to place several applications within a single Linux image, within reason, to exploit the shared copy of the operating system. The downside of this in a physical hardware environment is that you proliferate systems in your racks to the point of environmental collapse. This is where we are at this point; There is no space to install a new server in the computer room. If there were space, there isn't enough electric capacity entering the room to support the new hardware. Were there power, there isn't enough cooling in order to keep everything chilled given the additional heat load of the new system. Yes, you can exceed the capacity of the electric company to bring power into your computer room; come have a peek, and welcome to my world... Having said that, all our Linux images, virtual and hardware-based, are single tasked. It is a Windows world, after all, and how do you fight the logic of the largest operating system company in the world.... -- Robert P. Nix Mayo Foundation .~. RO-OE-5-55 200 First Street SW /V\ 507-284-0844 Rochester, MN 55905 /( )\ ----- ^^-^^ "In theory, theory and practice are the same, but in practice, theory and practice are different." On 3/26/08 11:42 AM, "McKown, John" <[EMAIL PROTECTED]> wrote: > I'm wondering about this. I'm a z/OS person with some Linux knowledge. > But we don't run Linux on z around here. In the Windows world, the > mantra is generally "One server, one function". On z/OS it is the > opposite of "one server, lots of functions". How does Linux, in general, > stack up on this scale? It is better to have multiple guests, each doing > a specific job. Or is it better to have multiple functions in a single > guest? Yeah, I know, "it depends!". I am fairly sure that if a Linux > system is very busy, that it would be better for it to be "stand alone". > But is the same true of low activity functions? No, I don't have any > examples of a "low activity function", maybe simple email. > > Just curious. > > Also, what do ya'll think of VMWare's "appliance" philosophy? I.e. > instead of having a generalized Linux (or other) system which can do > many things, each "appliance" does one thing and is specialized to do > that only. When you want to upgrade, you replace the entire appliance, > OS and application, as a single "black box". ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
